Science, culture, complexity

Tag: noise pollution

  • Rule o flaw — part I

    This building right opposite my apartment was locked in a legal dispute for years. That must have ended a month ago (in October) because since then a bunch of workers have been toiling nine hours a day, six days a week to take it apart piece by piece. The contractor the building’s owner hired brought along a large excavator to push the walls of the four-storey structure down and it was done with most of the walls and one floor in a few days. But then trouble struck.

    The next day the contractor had the excavator driven away and replaced it with a pair of pneumatic jackhammers driven by compressed air. These were, and are, very loud machines. The pumps for the compressors were driven by the engines of two tractors parked downstairs. The jackhammers were loud as well, and workers had to hold them as they chipped away at the walls and floors piece by small piece. Why didn’t the contractor persist with the excavator? My father went over to have a chat with him and discovered the reason.

    About three buildings down from the one being torn down is the two-storey house of some Dravida Munnetra Kazhagam (DMK) bigwig. When the excavator was working, mechanical vibrations passed into the ground and rattled the walls of that guy’s house. And as a bigwig, the guy pulled some strings and got a senior police officer to intervene on his behalf, preventing the contractor from using the excavator. Funny thing is that the vibrations from the excavator’s demolition didn’t affect the three buildings before the bigwig’s house or the building housing my and five other apartments, nor various other houses on either side.

    The bigwig had built his house on a weaker foundation and was worried it would collapse and he believed it was okay to risk the peace of everyone else in the neighbourhood than risk that possibility — or, better yet, remedy that actual problem. I’m more sensitive than most to loud sounds and to the possibility that India’s Noise Pollution Rules are among the least invoked vis-à-vis complaints of public nuisance. But acting in such terribly bad faith, with no regard for one’s neighbours or the workers (although that’s on the contractor too), is sickening.

  • The frustrating wait for quiet in Chennai

    It was a Sunday. Around 7 am, I was woken by the sound of an auto idling outside my house. It had one of those loud put-putting engines, and the driver had parked the vehicle there waiting for one of my neighbours to step out. The noise echoed sharply around my block and was audible from everywhere within my house three floors above. Just as I prepared to step out and have a word with the driver, the idling stopped.

    Just across the road from my house is a vendor of construction materials. Its proprietor runs a loud business. His resupply trucks arrive in the dead of night to offload sand and bricks. During the day, his employees are often heard shouting at each other as they work. During the weekends, they bring out a wood-cutting machine that shrieks loudly as they use it for several hours in the afternoon.

    As the day wears on, the occasional canine screaming match breaks out nearby. At just around 10 am, another neighbour up the street revs his silencer-less motorcycle up before leaving for wherever he does at 10 am every day. The hawkers turn up one by one, blaring their wares and services — tender coconut water, fresh vegetables, “sofa repair”, spices, flowers, iron-whetting, and of course the kabadiwalas — in recorded voices blaring through small yet boisterous loudspeakers. These sounds are all crisscrossed by horn and engine noises from other vehicles passing by.

    Often the only way to find silence here is for the Sun to beat down hard. That way no one steps out in the afternoon. I don’t even find birds on the pea tree outside. That’s also a cruel thing to wish for, but even if it’s just a little cloudy, the hawkers keep coming and going. The pea tree is a popular local source of shade: come 4 pm and a bunch of Swiggy delivery guys gather underneath for a chat, maybe a glass of tea. Their voices can be comforting, a reminder that you’re around other people. When you’re looking for just a minute of silence, however, it’s yet another irritant.

    The day is a continuous drizzle of sounds but you’re probably thinking it’s an essential, even desirable part of city life — especially life in Chennai, with its oft-village-like vibes. But listening to them in isolation, as the government often seems to do, misses the point. There are of course the sounds we need, even desire: birds chirping at dawn, a fan creaking on a hot summer day, laughter from the neighbours’ houses, children making their way to school (and the sounds of band practice in the distance), voice lifting into the wind from the tea stall nearby… One of my neighbours practices playing the flute at night and he’s already very good at it. Another goes to bed listening to old Tamil film songs. I love them all.

    These are sounds. Then there’s noise. Imagine it is raining constantly, relentlessly where you are and then one day there’s a storm. You haven’t worn dry clothes in a long time. The storm subsides soon after yet the pitter-patter rain continues. I expect you’d be quite irritable and just wishing the Sun breaks out soon. Noise, constant noise is like this — sounds born of a social order that has long forgotten their intrusive nature. You don’t have a moment’s peace. Your ears, and heart and mind, are constantly responding to something. Unless you’re really, really good at spacing out or can afford noise-cancelling earphones, there is no escape.

    Even so, it might have been easier to deal with if the drizzle was all there was, but no. The evenings are the worst. There are two temples nearby. On any auspicious day — and there are about a dozen in a single month — devotional songs blare on loudspeakers. If the day is particularly auspicious, there are motorised floats bearing large idols lit by hundreds of LED lamps that, for some reason, face straight ahead. On Vinayak Chathurthi, a few such lamps lit up every front-facing apartment in our building through thick curtains at 4 am. Almost every Sunday evening there’s devotional karaoke on loudspeakers. Their only grace is to wind up at 10.30 pm, except of course if the occasion is, again, particularly auspicious.

    My house is near those of two well-known Kollywood actors and about 200 metres away from a Dravida Munnetra Kazhagam bigwig. There’s almost always a police car patrolling the neighbourhood, yet the cops never question the noise or when it begins or ends. Even on Vinayak Chathurthi, these weren’t the folks to respond when a loud drum-beating procession set off from the temple at 12.40 am. The devotees piped down only after two policemen paid them a visit after I’d given them a ring on phone numbers the Greater Chennai Police had tweeted.

    Even on less auspicious days, the ordeal isn’t done yet. The users of our local public dustbin don’t segregate waste. When the trash-collection vehicle rolls around at 11.30 pm, the workers attach each bin to its handles, and the driver then has the mechanism smash the bin against the rim of the container to ensure the bin yields its jumble of contents no matter how mucilaginous they’ve become. That slow-mo bang-bang-bang is in fact how the whole neighbourhood knows it’s nearly midnight.

    Then finally there’s quiet, unless of course another barking match hasn’t already broken out.

    ***

    Deepavali is coming up, and since the first week of September I’ve been enveloped with dread. The noise from firecrackers in the city — whichever city — has graduated from being part fun, part nuisance to just harmful. The Supreme Court’s mandate to firecracker manufacturers and consumers to switch to ‘green’ crackers did nothing to mitigate the demand itself, which is to say the kind of pollutants entering the air has changed — from more to less toxic — but the quantities may not have.

    The court required these green firecrackers to be less noisy as well, but the new noise range is ironically no less harmful. They emit an estimated 100-130 dB, whereas research has registered harmful effects due to noise from 50 dB onwards and often considers 120 dB to be the threshold of human hearing — the point from which more sound pressure on the ears leads to pain more than perception.

    A meta-analysis of studies with people from Canada, Europe, Japan, and the UK reported in 2014 that every 10 dB increase in traffic noise hiked the risk of developing heart disease by 8%. In a statement published in 2016, the American Academy of Nursing called noise “a public health hazard”. Other studies have linked extended noise exposure to stress, anxiety, cognitive difficulties, and depression. Some small studies in Indian cities, including Chennai, Jammu, and Vadodara, have reported an elevated prevalence of hearing loss among traffic police and auto-drivers.

    All these effects, but stress in particular, is compounded when people are exposed to loud sounds when they least expect it — such as in the middle of the day, near a place of worship or a school, or at any time after 10 pm. Likewise, a very loud noise that lasts only for a brief moment may not be reason enough for a complaint, but it could still damage humans’ auditory apparatus and send stress levels soaring, yet there are no noise-based sanctions when such events occur.

    On September 4, the Government of Tamil Nadu sanctioned funds for a project to produce a “noise map” of four cities in the State with more than a million inhabitants: Chennai, Madurai, Coimbatore, and Tiruchi. The project will install noise monitors near airports, railway stations, high-traffic roadways and intersections, and areas with industrial and construction activity, as well as in spots that require quiet, like near schools, places of worship, and hospitals.

    Following the announcement, the Additional Commissioner of Police (Traffic) for Chennai, R. Sudhakar, told The Hindu that based on the project’s findings the city may adopt a system in which “decibel meters are installed at traffic signals. If noise levels exceed a certain threshold due to honking when the signal is red, the signal will reset and remain red for longer.”

    I have every confidence in my compatriots to find ways to render such social engineering meaningless, if not counterproductive. What if there is a lone miscreant among the drivers waiting for a signal to change who wastes others’ time by blaring his horns at the last second? What if there is an ambulance or cop car that really needs to make its way to the front? The noise monitor may just falter in Chennai’s incessant heat and humidity. Or an informal market may erupt in each city for horns emitting sounds at frequencies that evade the monitor yet are still audible to vehicles nearby.

    The State’s new noise-mapping exercise is (currently) restricted to permanent or semi-permanent sources of noise and doesn’t address the more common transient ones. Such sources include all those that haunt my neighbourhood and presumably most neighbourhoods in large cities. Their principal threat isn’t their isolated loudness per se — although that’s bad enough — but their interminability. By populating every moment with sound, they exacerbate the absence of quiet and heighten the consequences that other particularly loud sounds provoke.

    Noise pollution in India is no joke but given the wildly varying realities with which the country often confronts its own laws, the Noise Pollution (Regulation and Control) Rules 2000 are amusing. The Rules demarcate the hours of daytime (6 am to 10 pm) and nighttime (10 pm to 6 am) and four kinds of spatial areas. In daytime, the noise limit in industrial areas is 75, in commercial areas 65, in residential areas 45, and in “silence zones” 50.

    In all cases the unit is dB(A) Leq, which has an important physical meaning. ‘dB’ stands for decibel, a unit that expresses not an absolute value but the ratio between two values. When used to measure the loudness of sound, a dB denotes how many times more a given sound is louder than the threshold at which human hearing begins (a sound pressure of 20 micropascal). The ‘A’ in brackets refers to the use of a weight scale that combines a given amount of loudness with a constant that represents the perception of the human ear. Leq means the decibel value is a time-average — but this isn’t equal to adding up all the dB(A) values and dividing by the number of values. Because the decibel is a logarithmic measure, computing the Leq requires us to convert the dB(A) figures to sound-pressure levels first, calculate their average, and finally convert back to dB(A).

    This mathematical exercise throws up a crucial perspective. The Noise Pollution (Regulation and Control) Rules 2000 allow people to register a complaint if some activity breaches the specific threshold by more than 10 dB(A) Leq. If, say, there is a loud sound of 80 dB(A) Leq for 20 seconds every minute, and this plays out for an hour, the average noise level comes to 75.22 dB(A) Leq in this period — which is just enough to lodge a complaint in a “silence zone”, a residential area or a commercial area, and not in an industrial area. But it will not be enough if the average is calculated throughout daytime. In any case, the police is unlikely to admit a complaint against the simple hawker responsible for that 20-second blip.

    To make matters worse, Chennai and most other cities are haphazardly planned. Residential and commercial areas often spill into each other — assuming there has been a noise-wise zonation exercise. Even if they are chockablock, sounds carry over. It is thus a Kafkaesque challenge to register a complaint for violating the Rules unless the violation is altogether egregious. Even then, however, the damage to human (and animal) health is already done.

    (The US National Institute of Occupational Safety and Health recommends its Sound Level Meter app — simply called NIOSH SLM — for smartphones. It “ measures workplace noise to determine if workers are exposed to hazardous noise. The free app combines the best features of professional sound levels meters and noise dosimeters into one simple tool.”)

    ***

    I spent many of my childhood years in my grandparents’ house in T Nagar, opposite Ranganathan Street — a very crowded and noisy part of Chennai. There was always some sound around us. If it lapsed we’d know something was very wrong. It never did, of course. When I first travelled to Dubai, Sweden, and New York, I found the lack of ambient sounds unsettling, but over time I also got used to it, especially once I moved to Bengaluru in 2018, where my house was relatively secluded. Since then noises have frightened me, especially sudden ones, but I don’t feel badly about it. In fact I’m happy I lost the ability to be okay with it, an ability repeatedly souped up by less-than-ideal living conditions normalised by others around me.

    If there is noise everywhere in space and time, the question of who can afford quiet becomes important. When I lived in Delhi, it was readily apparent that only a certain class of people could access clean air and the benefits for well-being such access conferred. The air is on paper a part of the commons but in the national capital, especially during winter, there were only three ways to find clean air: live in the upper parts of a high-rise building, live near or in places with access to large green parks, or get an air-purifier or two. All of these things are expensive, so the poorer and the more marginalised had less access to clean air.

    In much the same way, quiet is becoming synonymous in Chennai with the upper-class, upper-caste experience of life given that it requires homes located far from thoroughfares, sound-proofing material, and expensive consumer electronics. Even on the road, quiet exists inside cars but is lost to every other mode of transport. Many of us are familiar with parents allowing their children to throw loud and protracted tantrums on public transport, but if shushing them is taboo, what of those with the deafening cellphone ringtones, those who speak loudly no matter where they are, and those who see fit to watch videos on full volume while you’re trying to sleep on the next seat?

    In a country in which pollution of some form is almost everywhere, noise pollution appears to be the most acceptable and tolerated. Deepavali is now less than a month away, but then it is also the storm amid the drizzle that just won’t abate.

  • India has a right to noise

    Excerpt from ‘More light, less sound: On firecrackers and a festival of light’, an editorial in The Hindu on November 7, 2023:

    The Noise Pollution (Regulation and Control) Rules 2000 stipulate that firecrackers cannot be burst in ‘silence zones’, designated by State governments, and anywhere after 10 p.m. From 6 a.m. to 10 p.m. (i.e., ‘daytime’) and in industrial areas, firecracker noise cannot exceed 75 dB(A) Leq. The thresholds in commercial and residential areas are 65 dB(A) Leq and 55 dB(A) Leq, respectively. … Traffic noise has burgeoned in cities where haphazard development has forced motorists to overuse horns. Many religious occasions have become synonymous with noisy celebrations irrespective of the hour. … If, say, people burst firecrackers at 90 dB for 10 seconds and the ambient noise is 50 dB for 50 seconds, and this pattern continues for four hours followed by 12 hours of 50 dB noise, the 16-hour Leq is 74.5 dB – which merits a complaint in residential areas but not in commercial ones, yet the noise is already harmful. Different loudness zones are also seldom publicly demarcated while some places are both residential and commercial.

    India has a big noise pollution problem, and firecrackers add to it in a bad way because the Noise Pollution Rules 2000 and improper urban zoning have together created a regulatory sieve through which firecracker noise can pass through without any consequences – except damage to human (and animal) health.

    To the issues highlighted in the editorial, I’d like to add one that complicates both enforcement and judicial disputes: the argument that asking people to not combust firecrackers violates their right to religion. The national and state governments in India have kept the door open to this assertion by refusing to ban loud firecrackers altogether, instead creating allegedly ‘green’ alternatives that also produce less noise: around 120 dB instead of around 150 dB, which is laughable because the healthy threshold is somewhere around 40 dB!

    On November 3, Justice Amit Rawal of the Kerala high court directed authorities to seize “illegally stored” firecrackers in temples across the state and ensure temples didn’t combust firecrackers at “odd time”. He added: “prima facie there is no commandment in any of the holy books to burst crackers for pleasing the god”. But today, November 7, a division bench set aside a part of the order to effectively reassert the terms set out in the Noise Pollution Rules 2000.

    Before this, the state government had submitted, according to On Manorama, “that there are several religious festivals in the State wherein display of fireworks is an essential part of religions, which have been carried out since time immemorial”.

    It’s unfortunate that we wield the right to religion maximally, to the expense of all other rights, and stop only when it’s confronted by an apparently implicit order of rights in the Indian Constitution. For example, by refusing to ban (noise) polluting firecrackers altogether, and by making the Rules so complicated, neither collecting nor easing public access to noise data, and slipshod urban planning (an oxymoron, really), India’s governments often leave the right to religion in conflict with the right to life. In the Constitution, however, the latter takes precedence.

    In early 2021, for example, the Madras high court was hearing a case about allowing the Srirangam Temple authorities to conduct their rituals in full rather than in an abridged form due to limitations imposed by the government in response to the COVID-19 pandemic. The court observed that the right to religion was superseded by the right to life, so if the rituals had to be abridged for the sake of public health, they wouldn’t violate the right to religion. 

    The Telegraph also reported that the court “alluded to the Calcutta High Court’s earlier order to regulate crowds during Durga Puja for the same reason. It may be recalled here that the Supreme Court had ordered restrictions for Ratha Yatra in Odisha too.” I think courts have made similar observations vis-à-vis Deepavali firecrackers as well as the winter-time pollution in North India.

    The right to life is predicated on threats to individuals’ well-being, which in turn is rooted in – among other things – where scientists are able to draw the line between good health and ill-health. For example, India’s permissible thresholds are higher than those of the WHO for different atmospheric pollutants. Biologically, people can (and often do) fall ill when the limits cross the WHO’s thresholds – but legally, we must wait for them to cross thresholds encoded in the relevant Act before we can claim injustice.

    Similarly, loud noises are harmful beyond 50 dB itself (depending on the level and mode of exposure), but the Rules’ thresholds are even higher. In fact, they may well be out of reach: India also has too few noise monitors for its size, which means even after scientists draw the line between ‘good’ and ‘bad’ noise levels, we may not know whether the place we’re located in has crossed over.

    And so we go, round and round…

  • Skyward light, wayward light

    This is welcome news:

    … even if it’s curious that three of the four officially stated reasons for designating this ‘dark sky reserve’ aren’t directly related to the telescopes, and that telescopes had to come up in the area for the local government, the Indian Institute of Astrophysics (IIA) and whoever else to acknowledge that it deserved to have dark skies. I believe that ‘doing’ astronomy with telescopes shouldn’t be a prerequisite to “promoting livelihoods through … astro-tourism” and “spreading awareness and education about astronomy”. And that’s why I wonder if there there are other sites in the country that are favourable to a popular science-driven activity, where the locals can be taught to guide tourists to pleasurably perform that activity, but which hasn’t been done because scientists aren’t there doing it themselves.

    But frankly, the government should declare as much of the country a dark-sky reserve as possible*, in consultation with local stakeholders – or at least a new kind of ‘reserve’ where, say, light, noise and other neglected forms of pollution are limited to a greater degree than is common by law and to encourage sustainability along these axes as well. This is in opposition to dealing with these irritants in piecemeal or ad hoc fashion, where each type of pollution is addressed in isolation (even when they have common sources, like factories), and – to a lesser extent – not just because scientists require certain conditions for their work.

    (* I’m obviously cynical about instituting large-scale behavioural change that’d preclude the need for such reserves.)

    Case in point: the new Hanle dark-sky reserve hasn’t been designated as such under law but through an MoU between the UT of Ladakh, the IIA and the Ladakh Autonomous Hill Development Council, with a commitment to fulfilling requirements defined by the International Dark Sky Association , based in the US. Fortunately – but sadly, considering we had to wait for an extraneous prompt – one of the association’s requirements is “current/planned legislation to protect the area”.

    Such ‘reserves’ also don’t have to be setup at the expense of development principally because many of the ways to reduce light (and noise) pollution can do so without coming in the way, of development as well as our right as citizens to enjoy public spaces in all the ways in which we’re entitled. (I’m asking for ‘less’ knowing the Indian government’s well-known reluctance to take radical steps to protect natural resources, but we’re also at a point from the PoV of the climate crisis where every gain is good gain. I’m open to being persuaded otherwise, however.)

    One of the simplest ways is in fact to have no public lighting installation that casts light upward, into the sky, but keeps it all facing down. Doing this will subtract the installation’s contribution to light pollution, improve energy-use efficiency by not ‘wasting’ any light thrown upwards and reduce the power consumed by limiting it to that required to illuminate only what needs to be illuminated, together with surfaces that limit the amount of light scattered upward.

    Other similarly simple ways include turning off all lights when you have no need for them (such as when you leave the room), to prefer energy-efficient lighting solutions and to actively limit the use of decorative lighting – but the ‘turn the lamps downward’ bit is both sensible and surprising in its general non-achievement. Hanle of course will be subject to more stringent restrictions, including requiring people to keep the colour temperature under 3,000 kelvin and the light flux of unshielded lamps to 500 lumen. Here’s an example of the difference to be made:

    That’s a (visibly) necessary extremum, in a manner of speaking – to maintain suitable viewing conditions for the ground-based telescopes in the area. On the other hand, India’s (and the UAE’s for that matter, since I was there recently) industrialisation and urbanisation are creating an unnecessary extremum on the other hand, giving seemingly trivial concerns like light pollution the slip. A 2016 study found that less than 10% of India is exposed to “very high nighttime light intensities with no dark adaption for human eyes” – but also that around 80% of the population is exposed to between “from 1 to 8% above the natural light” to complete lack of access to “true night because it is masked by an artificial twilight”.

    The tragedy, if we can call it that, is exacerbated when even trivial fixes aren’t implemented properly. Or is it when an industrialist might look at this chart and think, “We’ve still got a lot of white to go”?

  • India’s Delhi-only air pollution problem

    I woke up this morning to a PTI report telling me Delhi’s air quality had fallen to ‘very poor’ on Deepavali, the Hindu ostensible festival of lights, with many people defying the Supreme Court’s direction to burst firecrackers only between 8 pm and 10 pm. This defiance is unsurprising: the Supreme Court doesn’t apply to Delhi because, and not even though, the response to the pollution was just Delhi-centric.

    In fact, it’s probably only a problem because Delhi is having trouble breathing, despite the fact that the national capital is the eleventh-most polluted city in the world, behind eight other Indian ones.

    The report also noted, “On Saturday, the Delhi government launched a four-day laser show to discourage residents from bursting firecrackers and celebrating Diwali with lights and music. During the show, laser lights were beamed in sync with patriotic songs and Ramayana narration.”

    So the air pollution problem rang alarm bells and the government solved just that problem. Nothing else was a problem so it solved nothing else. The beams of light the Delhi government shot up into the sky would have caused light pollution, disturbing insects, birds and nocturnal creatures. The sound would no doubt have been loud, disturbing animals and people in the area. It’s a mystery why we don’t have familial, intimate celebrations.

    There is a concept in environmental philosophy called the hyperobject: a dynamic super-entity that lots of people can measure and feel at the same time but not see or touch. Global warming is a famous hyperobject, described by certain attributes, including its prevalence and its shifting patterns. Delhi’s pollution has two hyperobjects. One is what the urban poor experiences – a beast that gets in the way of daily life, that you can’t wish away (let alone fight), and which is invisible to everyone else. The is the one in the news: stunted, inchoate and classist, it includes only air pollution because its effects have become unignorable, and sound and light don’t feature in it – nor does anything even a degree removed from the singular sources of smoke and fumes.

    For example, someone (considered smart) recently said to me, “The city should collect trash better to avoid roadside garbage fires in winter.” Then what about the people who set those fires for warmth because they don’t have warm shelter for the night? “They will find another way.”

    The Delhi-centrism is also visible with the ‘green firecrackers’ business. According to the CSIR National Environmental Engineering Research Institute (NEERI), which developed the crackers, its scientists “developed new formulations for reduced emission light and sound emitting crackers”. But it turns out the reduction doesn’t apply to sound.

    The ‘green’ crackers’ novel features include “matching performance in sound (100-120dBA) with commercial crackers”. A 100-120 dBA is debilitating. The non-crazy crackers clock about 60-80 dBA. (dB stands for decibels, a logarithmic measure of sound pressure change; the ‘A’ corresponds to the A-setting, a scale used to measure sounds according to human loudness.)

    In 2014, during my neighbours’ spate of cracker-bursting, I “used an app to make 300 measurements over 5 minutes” from a distance of about 80 metres, and obtained the following readings:

    Min: 41.51 dB(A)
    Max: 83.88 dB(A)
    Avg.: 66.41 dB(A)

    The Noise Pollution (Regulation and Control) Rules 2000 limit noise in the daytime (6 am to 10 pm) to 55 dB(A), and the fine for breaking the rules was just Rs 100, or $1.5, before the Supreme Court stepped up taking cognisance of the air pollution during Deepavali. This is penalty is all the more laughable considering Delhi was ranked the world’s second-noisiest city in 2017. There’s only so much the Delhi police, including traffic police, can do, with the 15 noise meters they’ve been provided.

    In February 2019, Romulus Whitaker, India’s ‘snake man’, expressed his anguish over a hotel next door to the Madras Crocodile Bank Trust blasting loud music that was “triggering aberrant behaviour” among the animals (to paraphrase the author). If animals don’t concern you: the 2014 Heinz Nixdorf Recall study found noise is a risk factor for atherosclerosis. Delhi’s residents also have the “maximum amount of hearing loss proportionate to their age”.

    As Dr Deepak Natarajan, a Delhi-based cardiologist, wrote in 2015, “It is ironic that the people setting out to teach the world the salutatory effects of … quietness celebrate Yoga Day without a thought for the noise that we generate every day.”

    Someone else tweeted yesterday, after purchasing some ‘green’ firecrackers, that science “as always” (or something similar) provided the solution. But science has no agency: like a car, people drive it. It doesn’t ask questions about where the driver wants to go or complain when he drives too rashly. And in the story of fixing Delhi’s air pollution, the government has driven the car like Salman Khan.

  • Measuring loudness on Deepavali nights

    The Indian festival of Deepavali gets its name from the Sanksrit for “display of lights”, “Deepaanaam aavali“. These days, the festival is anything but about lights, especially in urban centers where the bursting of loud firecrackers has replaced the gentler display of lamps. Sometimes, Bangalore – where I live – sounds like a warzone. People I’ve spoken to have defended the way they celebrated it, saying, “It’s a tradition thousands of years old!” No, it’s not.

    The Noise Pollution (Regulation and Control) Rules 2000 (“Rules”) limits the amount of environmental noise by area and time of day. In residential areas, for example, the maximum allowable noise level between 6 am and 10 pm (‘daytime’) is 55 dB(A) Leq.

    A Central Pollution Control Board document released on October 24 reports the results of an exercise where noise-level monitors listened in in five areas of the national capital, Delhi, for the week leading up to Deepavali: October 15 to October 23. Without exception, the dB(A) Leq readings in all five areas – Pragati Maidan, East Arjun Nagar, NSIT Dwarka, IHBAS Dilshad Garden and DCE Bawana – have increased from 2013 to 2014. The nighttime readings breach the Rules limits by at least 10 dB(A), which warrants a complaint.

    Insofar as the Rules is concerned, the units of measurement play a defining role in how meaningful the limits are.

    For starters, dB stands for decibels, a logarithmic measure of noise levels. According to ISO standards, a doubling of noise levels is equal to an increase of 3 dB.

    Because noise levels during many kinds of measurements – including during Deepavali – keep changing, Leq is used because it denotes an average noise level during a specified period. Moreover, because dB is a logarithmic measure, Leq cannot be calculated like a simple average. Instead, sound-meters usually convert dB into the corresponding sound pressure levels and then calculate the average. In the process, the A-setting is also applied: it is a scale to measure the perceived human loudness.

    As it is, the Rules don’t explicitly specify the time period across which the noise levels are to be measured. The only mention of periods, in fact, is when the document defines daytime (6 am to 10 pm) and nighttime (10 pm to 6 am). So the noise level of 55 dB(A) Leq is presumably defined for a 16-hour period (daytime; residential area). An obvious outcome of this is that infrequent loud noises in a generally quiet residential area will not breach the legal limits during daytime.

    But what about during Deepavali? Let’s say the festival is being celebrated on a weekday: the bursting of firecrackers will start around 4 pm (once the kids have returned from school) and last until 9 pm. Could noise levels in this five-hour period push the daytime average beyond 55 dB(A) Leq?

    I used the NoiseTube project’s mobile app (of the same name) that makes per-second measurements and calculates the minimum, maximum and average dB(A) Leq over a specified duration. Sitting about 80 m from a bunch of kids bursting firecrackers in our apartment driveway, I used the app to make 300 measurements over 5 minutes for the following results:

    Min.: 41.51 dB(A) Leq
    Max.: 83.88 dB(A)Leq
    Avg.: 66.41 dB(A) Leq

    Earlier in the day, I’d made a five-minute measurement when no firecrackers were being burst for an avg. reading of 42 dB(A) Leq. So, assuming that 42 dB(A) Leq was the reading for 11 hours and 66.41 dB(A) Leq for the remaining five, the daytime average reading comes to 56.53 dB(A) Leq. Abiding by the Rules, this isn’t even enough for me to register a complaint, which necessitates the noise levels to exceed the limit by at least 10 dB(A).

    At the same time, the noise levels are debilitating. When the cracker-bursting frenzy is in full swing, I’ve recorded noises louder than 100 dB(A). If I spend a day outside, and if the sulfurous fumes don’t give me a migraine, just the noise will.

    Because of this, the Rules might be more meaningful – and effective – if a measurement duration is defined, such as between certain times of day according to what time of the year it is (correct me if I’m wrong because I’d love to be wrong about this). In fact, because dB is logarithmic, any average will be biased toward the higher values (as exponentially higher the numbers, higher the logarithms), and even with this boost, 66.41 dB(A) Leq over five hours is not ‘illegal enough’.

    Featured image from Wikimedia Commons