A sigh of relief!

The national capital has been known rather world-wide for its toxic air and degraded environment owing to the rapid pace of reckless development and belligerent modernisation; the crisis compounded by the convenient agricultural practice of burning stubbles in nearby states. Commendable efforts of the Delhi government have mitigated the situation to a palpable extent. We know this because four years after a World Health Organisation study declared Delhi the world's most polluted city, Chief Minister Arvind Kejriwal stated that pollution in the city has dropped 25 per cent since, especially in terms of concentration of particulate matter. The most polluted city in the world has since then geared up and got its act together to curb pollution quantitatively and create an impact qualitatively. The Centre, states, and courts have got together to take several steps to arrest pollution in the city. Through its pollution control committee, the Delhi government set out to monitor the air quality in real time in 2010, beginning with just four stations (in R K Puram, Punjabi Bagh, Anand Vihar, and Mandir Marg). With crop-residue burning in full force that year in October and November, 2012 was the year when Delhi suffered its worst air quality. 2012 was also the year when for the first time the common practice of burning stubbles was seriously flagged and it was realised that this was a major reason for the sudden dip in air quality in Delhi. And since 2012, the average annual concentration of particulate matter, which is the primary cause of pollution in the city, has been declining, gradually in the beginning and dipping more sharply between 2015 and 2018. In a move to step up the pollution control programme, last year, 2018, there was an increase in the number of air quality monitoring stations to 26. Focusing on the aspect of particulate matter is especially important as it is a mixture of solid particles and liquid droplets in air which easily make their way into our lungs and a concentration of these is severely hazardous to health, and even life. Some of these particles can be seen with the naked eye while others are microscopic. The primary pollutants in Delhi's air are PM 2.5 (these are inhalable particles of 2.5 micrometres diametre or smaller) and PM10 (of 10 micrometres diametre and smaller). November is the month when highest volume of crop residue is burnt in Haryana, Punjab, and Uttar Pradesh. This is also the time when temperatures fall and humidity rises, causing an increase in concentration of pollutants in the air. Hence, the onset of winter is a time of heightened pollution in the national capital and efforts to mitigate that are made before hand. A result of this is that in 2012 and 2018, the concentration of PM10 reduced by 21 per cent from an average 351 micrograms/cubic m to 277 micrograms/cubic m. Delhi's performance in terms of PM10 concentration has been encouraging in so far as August this year. As much as constructions and vehicular pollution contribute to the bad air quality, several studies have established that the localised weather conditions and seasons are among the biggest determinants of Delhi's air quality. And despite the vagaries of the weather, the efforts of the government have borne fruits over the past few years and point to the fact that not only do efforts need to be made, but when done so consistently, the results are encouraging and that things can be improved tremendously.

What has particularly helped Delhi is its government's efforts curb vehicular pollution, especially from diesel, as well as the odd-even road rationing scheme during peak seasons of air pollution. After a lawyer Vardhaman Kaushik, in 2014, approached the National Green Tribunal (NGT) against pollution levels, his petition became the basis of several NGT orders upheld by the Apex Court. The ban on old diesel and petrol vehicles was a very impactful order under this. Subsequently, between 2014 and 2017, the Delhi government, Central Pollution Control Board, and Environment Pollution (Prevention and Control) Authority executed drives, issued orders, and implemented orders passed by NGT to curb air pollution. The most significant push has been in 2017 when the Centre notified the Graded Response Action Plan (GRAP) providing state governments in Delhi and the Nation Capital Region with a roadmap for action. This included contingency measures like if the air was severely polluted for more than 48 hours, the entry of trucks would be stopped, and all construction work halted. The GRAP also set roles for each agency, fixing accountability. Shutting down two thermal power plants in Delhi, completing the eastern and western peripheral expressways for vehicles not bound for Delhi, ban on PET Coke as an industrial fuel, the introduction of BS VI fuel are some of the significant administrative changes that have contributed to Delhi's air. Clearly, since good air is the rightful need of all breathing it, institutions at different levels coming together to make it cleaner is a heartening example of coordinated work for general good and public welfare.