Desperate for clean air in national capital

The year 2015 came to a close with new energy driving air pollution control measures in Delhi. On December 16, the Supreme Court ordered that no one in the National Capital Region (NCR) can buy a luxury diesel car or SUV with engines bigger than 2000 cc. Trucks entering the capital will have to pay double the amount of environment compensation charge and trucks more than 10 years old cannot even enter the city. All taxis in NCR will have to switch to compressed natural gas (CNG) while all state governments in NCR will have to curb pollution from trash-burning and suspended dust from roads.

Meanwhile, under pressure to shake off the notorious tag of “gas chamber” that Delhi has earned, the state government has introduced the odd-even number formula on a trial basis. During the first fortnight of January, residents can ply their cars every alternate day depending on whether their registered car number is odd or even. The strategy is to remove at least 50 percent of personal vehicles from the city roads. The Delhi government has also proposed to shut the coal-based power plants in Badarpur and Rajghat during winter.

These are desperate times that need desperate measures. The alarming pollution levels in Delhi call for a war on pollution, and the Supreme Court has just cracked the whip.

Most of these directives are from the bench headed by the Chief Justice of India, Justice T S Thakur, to check the public health emergency in the city. To facilitate the implementation of the Supreme Court’s order, the Environmental Pollution Control Authority has issued directives to stop the registration of diesel buses and autorickshaws in NCR.

More orders are expected on emissions standards for vehicles and pollution from power plants. The Supreme Court order brings the entire NCR under the ambit of action. Delhi’s effort can create a template for clean air for other cities too. Air pollution today is a national crisis and the fifth-largest killer in the country, according to estimates of the Global Burden of Disease, 2012, a report of the World Health Organization.

Air pollution in the country’s capital has remained consistently high, despite a mixed trend over the years. About 15 years ago several measures were implemented under the direction of the Supreme Court. These included improved emission standards, public transport strategy on CNG, capping the age of commercial vehicles, improved vehicle inspection programmes, relocation of polluting industries and action on power plant pollution. These steps reduced the annual average PM10 (particulate matter less than 10 microns) levels in the city by about 16 percent between 2002 and 2007. But after 2007 only a few steps were taken—expansion of Delhi Metro, a moderate increase in bus numbers, Bharat Stage IV emissions standards for vehicles and a small network of cycle tracks and footpaths around Commonwealth Games venues. This was too little too late.

Particulate levels, the key target of policy action, increased dramatically by 98 percent between 2007 and 2014. In 2014, the annual average ambient PM10 levels reached five times the Indian standard of 60 microgrammes per cubic metre. On the other hand, PM2.5, the tiny particles less than 2.5 microns that go deep inside the lungs, have shown consistently high annual average levels since 2011 and is, at least, four times the standard. Between 2002 and 2014, the levels of nitrogen oxides (NOx) in the city also increased by 55 percent.

Ozone levels during a large number of days in the summer months in Delhi violate the standards. The city is in the grip of a multi-pollutant crisis. One can also witness a deadly blanket of winter pollution when the wind remains calm, cool and trapped close to the ground. Almost throughout the winter months of 2015, levels of PM2.5 reached up to four to seven times the standard. On days when smog is high, PM2.5 rises even higher. When the national air quality index was applied to daily air quality monitored by the Delhi Pollution Control Committee (DPCC), it was found that while in the month of October about three percent of the days were in the “severe” category, the worst category according to the index, by November, 63 percent of the days were in that category. This is extremely dangerous for people suffering from respiratory and cardiac problems and also for children and the elderly.

Several studies in Delhi provide local evidence on damaging health impacts of air pollution.

An epidemiological study on children in the city carried out by the Central Pollution Control Board (CPCB) and the Chittaranjan National Cancer Institute of Kolkata threw up scary results. The study, published in 2012, found that every third child in Delhi has reduced lung function. Sputum of children was found to contain four times more iron-laden macrophages than those from cleaner environs. The levels of these biomarkers in children were found to be higher in areas with high PM10 levels.

Global scientific studies, as well as those from cities of India, have associated air pollution with a number of health problems, including respiratory and cardiac problems, stroke, cancer, hypertension, diabetes and effect on the brain and foetus. Even though Delhi has taken steps to generate real-time data to track air quality, it is yet to issue public health alerts and advisories to help people take precautions. In many global cities, the pollution levels as recorded in Delhi would have been declared as pollution emergencies.

Nevertheless, in what can be called a beginning, air pollution and health evidence have spurred official and court action in the city.

Delhi can meet its clean air targets if it cuts emissions from multiple sources of air pollution in the city—vehicles, industry, power plants, open trash burning, construction and suspended dust from roads, among others. The most recent and detailed study of all pollution sources in Delhi has been carried out by the Indian Institute of Technology (IIT), Kanpur. The study was commissioned by the Delhi government and was discussed in the Supreme Court hearing.

According to the draft report of the study, the top four PM2.5 sources include road dust (36 percent), vehicles (20 percent), domestic fuel burning (12 percent) and industrial point sources (11 percent). Similarly, the top four NOx emitters are industrial stacks including power plants (52 percent), vehicles (36 percent), diesel generator sets (six percent) and domestic sources (three percent).

The relative position of the pollution sources changes through the summer and winter seasons. During winter, vehicles cause 25 percent of the PM2.5 problem; biomass 26 percent and trash-burning eight percent. The increased concentration of particulate matter from the end of October to November is also due to the effect of crop burning in neighbouring states like Punjab and Haryana. But in summer, coal and fly ash contribute the maximum to air pollution (26 percent), followed by soil and road dust (27 percent), biomass burning (12 percent), vehicles (nine percent) and trash-burning (seven percent).

The IIT study also estimated, for the first time in Delhi, secondary particles—gases in the air that form particles by reacting with each other in the air and add to PM2.5. NOx turns into nitrate particles and sulphur dioxide into sulphate particles. These can be as high as 30 percent of PM2.5 in winter and 15 percent of PM2.5 in summer. 

This also shows that combustion sources such as vehicles, industrial and power sources are much bigger culprits than dust as their gases further increase the overall particulate load. The study also found very high pollution in towns in the NCR region, including Noida, Faridabad and Ghaziabad that are usually not well monitored by the official monitoring agencies.

The message is clear. Urgent action in the short and medium term is needed on all key pollution sources across NCR to improve the quality of air in the airshed. The first ever draft report on air pollution and health prepared by the Union Ministry of Health and Family Welfare has underscored the importance of reducing exposures from pollution sources close to people. As urgent steps, decisions have been taken in Delhi to cut down toxic diesel emissions from trucks and big diesel cars and also close Delhi’s two most polluting coal-based power plants during winter. More decisions are to follow.