Bad air days return to haunt Delhi as winter approaches

NEW DELHI – Like clockwork, every year before the onset of winter, cold air and calm winds begin to trap

pollutants from farm fires, industries

and vehicle emissions

across northern India, transforming its air into a toxic cocktail for millions of its residents.

This year is no different.

India’s capital, New Delhi, has already seen the air quality index (AQI) jump to 313 on Sunday, taking it to the “very poor” level for the first time since May 17.

India’s air quality guidelines define an AQI of between 301 and 400 as “very poor”, while cautioning that such high pollution levels can cause respiratory illness from prolonged exposure.

The range for a “good” AQI rating is between zero and 50, something Delhi has recorded on just one day so far in 2023.

It has, however, seen more than 200 “moderate” days with AQI levels between 101 and 200.

The rise in pollution has led the authorities to implement the second stage of a Graded Response Action Plan that seeks to combat air pollution in the Delhi-National Capital Region (NCR).

Under this plan, people have to minimise use of personal vehicles and switch to public transport, and the authorities must intensify dust-control measures at construction sites, among other measures.

Since Sunday, the air quality in Delhi has improved somewhat, but it still hovered in the “poor” category with an AQI of between 201 and 300.

On Wednesday, when the Australian and the Netherlands cricket teams battled it out in a Cricket World Cup match in a Delhi stadium, the AQI was at 243. 

The air quality over the city is expected to decline in coming weeks as fumes from firecrackers let off during Deepavali, which falls on Nov 12, and more farm fires add to the pollution load.

New Delhi, which has been consistently rated as the world’s most polluted capital by IQAir, a Swiss air quality technology company, has taken steps in recent years to tamp down its pollution.

These include expanding its metro network, converting its public bus fleet to run on cleaner compressed natural gas instead of diesel, phasing out old vehicles and promoting electric ones, shutting down coal-fired power plants and forcing industries to switch to natural gas. 

These measures have led the city’s annual average level of PM2.5 particles to fall from 149 micrograms per cubic m of air in 2014 to 103mcg per cubic m of air in 2022. But a lot more needs to be done, given the scale of the problem.

According to the National Ambient Air Quality Standards, the prescribed limit for annual average level of PM2.5 particles is 40mcg per cubic m of air, while the World Health Organisation’s safe annual limit is even lower at 5mcg per cubic m of air.

A key gap that persists is the inadequate reach of public transport in a sprawling Delhi-NCR, which is home to around 20 million people, and an accompanying rise in the use of personal cars among the region’s affluent. The on-road vehicle fleet in Delhi has grown from 7.5 million vehicles in 2012 to more than 13 million in 2022.

Ms Anumita Roy Chowdhury, who heads the air pollution team at the Delhi-based non-profit Centre for Science and Environment, said that the city’s sheer volume of traffic has to be addressed with an integrated public transport system that provides convenient and reliable access to transportation.

This is on top of measures that support walking and cycling, and discourage use of personal vehicles. 

“This is important because vehicles in Delhi are now contributing to about half of the pollution problem,” Ms Chowdhury told The Straits Times.

Proscribed activities such as solid waste burning in the open and use of dirty fuels in poorly monitored industries outside demarcated industrial zones in the city are another problem, besides the use of wood as a cooking fuel by its urban poor.

“The whole focus has to be on implementation… We need to work on two levels – raise awareness not just about the problem, but also regarding the scale and speed of the solutions needed,” Ms Chowdhury added.

The slow progress in battling Delhi’s pollution crisis has led to growing calls to adopt an “airshed-level” approach, which involves coordinating anti-pollution efforts over a wider area that goes beyond state boundaries.

An airshed is an area where the movement of air, and air pollutants, can be hindered by local geographical features and weather conditions, causing it to become uniformly polluted.

Delhi’s airshed, which is estimated to span a region with a radius of around 150km to 200km, includes parts of other states such as Uttar Pradesh, Haryana, Rajasthan and Punjab.

Dr Gufran Beig, a chair professor at the National Institute of Advanced Studies in Bengaluru and the founder of India’s air quality services Safar, said as much as 30 per cent to 35 per cent of the peak annual pollution load in Delhi during the winter comes from multiple sources in neighbouring regions of this airshed.

This figure can vary during other seasons. 

Stubble burning, which occurs mostly in October to November, is just one of these sources.

It refers to the practice of setting fire to straw stubble that remains on farms after grains, such as rice, are harvested to clear the soil for the next crop. Open solid waste burning, industrial and vehicular emissions and the use of dirty cooking fuel also contribute significantly to pollution levels.

“When you act just locally in Delhi, it means you are addressing only around 65 per cent to 70 per cent of the problem and this makes the task of cutting pollution in the city even more difficult,” he told ST, calling for long-term mitigation measures across the entire airshed region.

The implementation of anti-pollution efforts beyond Delhi is weak, and multiple authorities across the city’s airshed region have struggled to coordinate their actions for better results.

In recent years, the winter pollution problem has gone beyond north India, affecting cities such as Mumbai, India’s financial capital on the Arabian Sea coast. 

The poor AQI there, which has been worse than that of Delhi on certain days, has been attributed to a lack of incoming sea breeze and unusually low wind speeds that have failed to disperse pollutants from key sources such as vehicles and industries, besides ongoing infrastructure projects and road dust suspension.

The authorities in Mumbai on Wednesday asked construction sites to use barricades to prevent wider dispersal of dust particles and banned garbage burning in open grounds. But implementation of these rules has been poor in the city, leading to its recurring pollution crisis.