by Bhavya Paliwal


Over the Diwali (the most important Hindu festival celebrated each year in India with family gatherings, glittering clay lamps, festive fireworks, strings of electric lights among other traditions) weekend of 2016, India’s air quality was among the world’s worst and between 40% and 100% worse in five north Indian cities than at the same time the preceding year, according to global air pollution data. On 30 and 31 October, 2016, parts of Delhi, recorded PM 2.5 levels of over 700 µg/m³–exhibiting “beyond scale” pollution values (one of the highest levels recorded world over and 29 times above WHO standards), according to the database run by Berkeley Earth, an independent US research organization (Madhavapeddi and Saldanha 2016).

This problem is of course of prime concern, considering the adverse health effects such high levels of air pollution can have on humans and environment. By one estimate the Delhi smog kills 10,500 people a year (The Economist 2012). Children are particularly vulnerable, a 2015 study found about half the Delhi’s 4.4 million school children had stunted lung development and would never completely recover (Safi 2016).

Despite coming in the news recently for these alarming figures, this is not the first time that Delhi is dealing with such a catastrophic air pollution problem. The problem of air pollution in Delhi is old and over the decades has just been worsening due to the massive population inflow into the capital city. The government of Delhi, previously has taken various measures to curb the air pollution, but clearly those measures have not been enough and the ever increasing inflow of people into the metropolitan keep adding to the already serious problem of air pollution.

Causes of Air Pollution

There are several sources of air pollution in the city – vehicles, industry, power plants, open trash burning, construction, suspended dust from roads etc. To add to that are its geography, location, weather, seasonality of the pollution and ever growing population. As a landlocked megacity Delhi has limited avenues for flushing polluted air out of the city. Delhi’s surrounding regions are sometimes even more polluted than the city. For example, most of the brick kilns used for making bricks are not located in the city, but in predominantly upwind surrounding industrial areas. These outside pollutants can be attributed to use of low-quality fuels such as raw wood, agricultural and plastic waste in industrial settings, cow dung for cooking stoves and widespread use of diesel generators due to unreliable infrastructure. These sources release fine particle pollutants, the most dangerous to human health. In Delhi fine particle pollution rates are ten times higher than that of Chennai, which has ten times more cars but is coastally located, without the surrounding industrial areas. Coupled with Delhi’s densely packed architecture, and varying building heights the ‘breathability’ of the city is inhibited by its weather conditions. The city’s decreasing temperature (attributed to the effects of pollution) draws outside polluted air into the city center, whilst windy, dusty conditions during summer exacerbate this problem (“Underlying Causes of Delhi’s Air Pollution Problems” 2017).

Like most megacities in developing countries, Delhi and its people have aspirations for development. This and the growing middle class with more disposable income to purchase personal cars and the numerous causes (some man made and others not) of air pollution in Delhi, make tackling and resolving the problem a complex one.

Policy Recommendations

For finding policy solutions, I think the first and best step is always to look for examples and situations where similar problems have existed before. Learning lessons from them and formulating policy based on previous policies lends us the advantage of knowing which policies work best (and which do not, even if they seem perfect on paper) and how to implement them.

Examples of Other Cities

For policy recommendations, my starting point will be three cities which faced similar air pollution problems- Beijing, Mexico City and Los Angeles- which faced the problem for similar reasons as Delhi and/or have same characteristics (big metropolitan cities with a huge population) as Delhi. I will do a brief analysis of each of the city- the problems they faced, the causes and their policy solutions. As is known from literature, no one policy fits all and consequently the context of a given case is very important in trying to find the policy which might work best. Hence, the most important step in taking this approach is to find examples which are most similar in terms of geography, causes, demography and problems as Delhi. I found that Mexico City in 1980s, Beijing in the 1990s and Los Angeles in 1960s had similar characteristics as present day Delhi.

In 1960s when California was building its economy after World War II, there were many cities wherein the air quality had severely deteriorated. In particular, Los Angeles and neighboring cities, like Riverside, were amongst the worst polluted cities in the world. California has made tremendous progress in reducing air pollution levels since the 1960s, by combining science, policy, governance, and technology (Ramanathan et al., 2014). At the same time, its population, number of vehicles, and diesel consumption increased by 100%, 175%, and 225%, respectively (Ramanathan et al., 2014), and its economy grew enormously (resulting in the largest GDP among all states in the US). Delhi faces similar challenges in terms of population and vehicle growth.

Beijing has been in the limelight for having bad air quality since 1990s. The scrutiny became even stricter in the 2000s when Beijing won the bid to host the Summer Olympics in 2008. Delhi and Beijing have many similar characteristics which makes taking Beijing’s example a relevant one. Both Delhi and Beijing are land enclosed (surrounded by mountains in the case of Beijing), which traps the toxic emissions. Both the cities are rapidly developing and have had a huge influx of population and vehicles in the past couple of decades. Matters are made worse for both the cities due to the toxic air coming in from the industries on the outskirts of the cities. To cure Beijing of its ills, city officials, after winning the bid to host the 2008 games, promised to spend $ 12 billion on environment cleanup to stage a “Green Olympics” (Stone 2008). With various policies put into effect, the pollution levels in Beijing significantly decreased. I examined these policies and see which of them might work well and in the long run in the case of Delhi.

Being a fast urbanizing city in a rapidly growing economy, with millions of people migrating into the city and being land locked, Mexico City too has numerous similar characteristics as Delhi. The city, not unlike Delhi, has grown at a tremendous rate with overcrowding, congested streets, and factories causing large amounts of pollution, that is not able to escape out of the city. Mexico City’s air pollution problem was highlighted in mid 1980s. In 1996, city and regional governments introduced “Management Programme to Improve Air Quality”. The package of reforms managed to bring Mexico City’s air pollution down from a dangerously high rating of 300 on its Metropolitan Air Quality Index (Imeca) in the 80s, by reductions in the concentrations of some pollutants such as lead, carbon monoxide and sulfur dioxide (“How Mexico City Slashed Air Pollution Levels by Half” 2017).

Lessons for Delhi

Having gone through various policy solutions for these cities, I am listing policy recommendations which I think may work best for Delhi. Since the causes for air pollution in Delhi are many and complex, it would be best to work on multiple factors of pollution together which will encompass households, industries and other facets of the city. The city should work on all these forefronts immediately and simultaneously to see results.

Let’s start with vehicles, since there has been a huge increase in the number of private vehicles in Delhi in the last decade. Many vehicles (both private and commercial) use diesel and retro fitment of Diesel Particulate Filter (which have PM emission reduction efficiency of 60-90% and will result in a reduction of 40% emissions). Another policy targeting diesel should be the reduction of the Sulphur content. Ultra-low Sulphur fuel will reduce PM10 and PM2.5 emissions from vehicles by about 6 % (Sharma and Dikshit 2016). Further there should be implementation of newer emission standards for all diesel vehicles including heavy duty vehicles (non-CNG buses and trucks). Electric/ Hybrid should be introduced and consumers should be incentivized to buy these. Along with these, vehicular emission norms/standards should be enforced for the new vehicles at the factories and the implementation of these new laws should be stringent.

For domestic fuel options for the poor in and around Delhi, Although Delhi is kerosene free and 90% of the households use LPG for cooking, the remaining 10% (poor in Delhi) and households in rural neighborhoods of Delhi uses wood, crop residue, cow dung, and coal for cooking (Census-India, 2012). The LPG should be made available to remaining 10% households to make the city 100% free from solid fuels.

Another prominent source of air pollution in Delhi is crop residue burning (CRB) in Delhi and neighboring states (which are predominantly agrarian) of Haryana and Uttar Pradesh. All biomass burning in Delhi should be stopped and strictly implemented. Managing crop residue burning in Haryana, Uttar Pradesh and other local biomass burning is important. Potential alternatives to CRB which can be implemented are energy production, Biogas generation, commercial feedstock for cattle, composting, conversion in biochar, raw material for industry etc. (Ramanathan et al., 2014).

There are approximately 9000 Hotels/Restaurants in the city of Delhi, which use coal (mostly in tandoors- oven clays). The PM emission in the form of fly ash from this source is large and contributes to air pollution. It is proposed that all restaurants of sitting capacity more than 10 should not use coal and shift to electric or gas-based appliances (Sharma and Dikshit 2016).

One of the reasons Municipal Solid Waste (MSW) is burnt in the city is lack of infrastructure for timely collection of MSW. In this regard, infrastructure for collection and disposal (landfill and waste to energy plants) of MSW has to improve and burning of MSW should be banned completely.

In a city like Delhi which is high in urban agglomeration, construction and demolition activities are frequent. This source is the third most contributor to area source emission in PM10 and importantly it is a consistent source all through the year. The control measures for emission may include: wet suppression, wind speed reduction (for large construction site), proper disposed of waste, proper handling and storage of raw material and storing the waste inside premises with proper cover. At the time of on-road movement of construction material, it should be fully covered. Another source of pollution is the ready mix concrete used for construction activities. The control measures for this include: wind breaker, bag filter at silos, enclosures, hoods, curtains, telescopic chutes, covering of transfer points and conveyer belts.

In summers, soil and road dust can contribute about 26% to PM10 and PM2.5. The silt load on some of the Delhi’s road is very high and silt can become airborne with the movement of vehicles, particularly in dry summer season. The estimated PM10 emission from road dust is over 65 tons per day. Similarly soil from the open fields gets airborne in summer. The potential control options can be sweeping and watering of roads, better construction and maintenance, growing plants, grass etc. to prevent re-suspension of dust (Sharma and Dikshit 2016).

Another solution to combat air pollution in general, without targeting a specific cause is to plant more trees. In Beijing, tree planting was proposed by the municipal government as a measure to alleviate air pollution. The trees in the central part of Beijing removed 1261.4 tons of pollutants from the air in 2002. The air pollutant that was most reduced was PM10 (Yang et al. 2005). Officials in Hebei Province, which surrounds Beijing, have decided to create what they call a “green necklace” of trees in hopes of clearing the air. They emphasized the need for “ventilation corridors” that would channel wind and air movement to help disperse smog (Wong 2017). Delhi could follow suit and implement the same idea to control smog and pollution.

Using these policies simultaneously will help Delhi in improving its air quality both in short run and long run. Since Delhi is struggling to reduce pollution, even as its population swells, the situation is pretty complex. Hence the only way to combat the air pollution of Delhi is to act on multiple fronts simultaneously.


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