Analysis of NASA satellite data shows a steady rise in PM2.5 levels since 2003 in India — a similar situation in China. But China put the brakes after pollution levels peaked in 2011 — also the worst year on record — following which pollution levels witnessed a downward trend with remarkable reduction across eastern and central China.

China’s particulate matter emissions started decreasing as 2015 witnessed a fall of 15 percent as compared to 2014. India, on the other hand, witnessed an increase of pollution levels at an average rate of 2 percent over the past decade.

In India, particulate matter emissions are the highest in the north — the National Capital Region recording a significant increase — with West Bengal, Bihar, Uttar Pradesh and Andhra Pradesh projecting the largest increases.

“Air pollution is a challenge in India. We need a national clean air action plan, so that cities can meet clean air standards,” said AnumitaRoychowdhury, executive director and head of air pollution and clean transportation programme, Centre for Science and Environment, Delhi. “All cities must adopt a mix of short term, medium, longterm and emergency strategies that must be rolled out at once.”

Taking note of rising pollution levels, the Delhi government introduced the odd-even car number policy as a pilot last month, while the Centre has announced its decision to move to Bharat VI vehicle emission norms by April 2020.

“There is an urgent need to set a deadline for meeting the national air quality standards with long term and interim targets and action plans. The plan should have mechanism to monitor the progress and empower authorities to take actions on compliance and noncompliance of the targets,” said Sunil Dahiya, Campaigner, Greenpeace India.

“The air pollution crisis is an opportunity to test India’s emergency response plan and design coordinated action for a ‘Clean Air Nation,”

According to World Health Organisation (WHO), 13 of the 20 most polluted cities in the world with deteriorating air pollution levels during past decade are in India largely covering north India.

While the country is likely to be home to more number of polluted cities, India’s National Air Quality network comprises 39 air quality monitoring stations as compared to 1500 stations in China.

According to the study, large cities such as Durgapur, Gorakhpur, Asansol, Shiliguri, Bareilly and Ludhiana though among the most polluted are outside the ambit of continuous air quality monitoring network.

“Though satellite data is being increasingly used to study air quality, it has its own uncertainty that needs to be accounted for. Comparison with data sets from other satellites as well as ground-based measurements must also be looked at, as also emissions from other polluting gases in addition to PM to ascertain the trend,” said professorRiteshGautam from the Indian Institute of Technology – Bombay (IITB)

HT had last year reported how pollution was creating holes in the dense winter fog cover over north Indian cities such as Delhi and other urbanized areas of the Indo-Gangetic Plains (IGP) based on satellite data sourced from NASA and analysed by Gautam. A long term analysis of winter fog over the IGP mapped from NASA satellite data from 2000 to 2014 for December and January revealed an increasing trend of both fog and pollutants over the eastern parts of the Indo-Gangetic plains — UP, Bihar, West Bengal and parts of Nepal and Bangladesh.

A report presented at the annual meeting of the American Association for the Advancement of Science early this month revealed that globally more than half of the 5.5 million premature deaths every year due to indoor and outdoor pollution occurred in China and India in 2013.

“China is an example of how determined policies and tougher enforcement can turn the tide on air pollution to people’s benefit,” said Lauri Myllyvirta, air pollution specialist with Greenpeace East Asia. “The Indian government needs to have plans to avoid the same disastrous health impact due air pollution has had in China.”