When toxic air chokes urban ecosystem

As the winter sets in, Indian cities are grappling with high levels of air pollution. Delhi, a megacity with the worst air quality as per a recent report by World Health Organisation (WHO), has recently adopted an emergency action plan to combat air pollution called the Graded Response Action Plan (GRAP). It is formulated by a Supreme Court-mandated panel and suggests a slew of measures to control pollution on 'severe' and 'very poor' air quality days in Delhi and its national capital region (NCR).

Bengaluru, which recorded near 46% rise in the level of air pollution this Diwali, aims to become the electrical vehicle capital of India. To this effect, the Karnataka government has announced its 'Karnataka Electric Vehicle and Energy Storage Policy 2017', which will not only make the state a hub for production of cleaner fuel vehicles, but also bring down air pollution and reduce dependence on the fossil fuels.
A recent report by the Indian Institute of Science on the transport sector of Bengaluru has suggested that by stressing on electric vehicles, the city can reduce emissions by 84% in 2030 and even 90% by 2050.

Apart from Delhi and Bengaluru, several other Indian cities have dangerously high levels of air pollution. For instance, the Central Pollution Control Board's (CPCB) data of September 2016 had ranked Hyderabad as city with the worst air quality among the monitored South Indian cities.

This year's Diwali data of the Telangana State Pollution Control Board showed the particulate matter with a diameter of less than 2.5 micrometres, or PM2.5, surged in Hyderabad to a 24-hour average of 112 μg/m3 as against the national daily average standard of
60 μg/m3. WHO has a much lower guideline limit of 25 μg/m3 for 24-hour mean PM2.5.

The situation was no better in Chennai where a cloud of smog descended on the city on the Diwali night. As per news
reports, the levels of PM10, another indicator of air pollution, touched 777 μg/m3 at Sowcarpet in north Chennai, which is four times the level compared to 180 μg/m3 last year. The daily average standard of PM10 is 100 μg/m3, as mentioned in the national ambient air quality standard of the CPCB.

A public health concern

Air pollution is a serious public health concern in India. 'The State of Global Air 2017', a special report on global exposure to air pollution and its disease burden has claimed that India's worsening air pollution caused some 1.1 million premature deaths in 2015. India has experienced the steepest increases in air pollution levels since 2010 and now has the highest PM2.5 concentrations among the countries studied in the report.

This is extremely worrisome because as per the WHO Global Urban Ambient Air Pollution Database, as urban air quality declines, the risk of stroke, heart disease, lung cancer, and chronic and acute respiratory diseases, including asthma, increases for those who live in the cities.

Air pollution is rising across the cities of the world. A new WHO air quality model, released last year, reported that 92% of the world's population lives in places where air quality levels exceed WHO's ambient air quality guidelines for ambient annual mean of PM2.5 at 10μg/m3. PM2.5 includes pollutants like sulphate, nitrates and black carbon, which penetrate deep into the lungs and in the cardiovascular system, posing the greatest risks to human health. The situation is worse in low and middle income countries, such as India, where 98% of cities with more than 1,00,000 inhabitants do not meet the WHO air quality guidelines.

Sources of air pollution

There are various sources of urban air pollution in Indian cities including inefficient modes of transport, household fuel and waste burning, coal-fired power plants and industrial activities. According to a 2010 report prepared by TERI, the major sources of PM10 in the city emissions are transport (42%), road dust re-suspension (20%), construction (14%), industry (14%), diesel generator (DG) sets (7%)  and domestic (3%).

For Delhi, a pollution source inventory and source apportionment study was carried out by the Indian Institute of Technology, Kanpur in 2015. This study assessed 13 key pollution sources and their relative contribution to different pollutants. Road dust (38%) dominated the particulate inventory in the study, followed by vehicles (20%), and industry and power plant sources (11%). In the case of nitrogen oxide inventory, industry (52%) lead with more than half the share, followed by vehicles (36%).

The study observed that vehicles were the most consistent and dominant sources of pollution throughout the year in Delhi, while most other sources were variable. Clearly, a variety of sources are contributing to air pollution in the urban centres, thus, cities need comprehensive plans to control the pollution.

Disaster alert system

According to the Centre for Science and Environment, New Delhi, air pollution is responsible for 10,000 to 30,000 deaths annually in the capital. Last November, the Supreme Court of India (SC) directed the government to frame and implement a Graded Response Action Plan (GRAP) to control air pollution. The Ministry of Environment, Forest and Climate Change notified the plan in January this year. This plan is designed like a disaster alert system, which directs governments to take tougher and tougher actions based on the level of air pollution.

The key measures, which are listed under the 'moderate' and 'poor' categories, are already in force through the year, with state governments monitoring progress. From October 17, 2017 to March 15, 2018 the 'very poor' and 'severe' categories have come into force in Delhi-NCR to curb dangerously high levels of pollution.

Various agencies in Delhi have been assigned actions to take when pollution touches moderate (air quality index of 101-200), poor (air quality index of 201-300), very poor (air quality index of 301-400) and severe levels (401-500), based on the air quality index. For instance, when PM2.5 levels cross 300 μg/m3 or PM10 levels cross 500 μg/m3, entry of trucks will be stopped (except essential commodities); and construction activities will also be stopped. If PM2.5 crosses 250 μg/m3 and PM10 crosses 430 μg/m3, brick kilns, stone crushers, hot-mix plants are to be shut down.

Whereas Delhi has put in place a legal plan to control air pollution, none of the other cities have such a plan to protect their residents from the impacts of air pollution. The cost of inaction is going to be insurmountable.