What is the real cause for Delhi’s air so polluted? Supreme Court’s recent order on ban on sale of firecrackers in the National Capital Region (NCR) is attempting to ascertain the “immediate impact of fireworks and firecrackers during Diwali”. According to an Indian Express report, at least four major government studies over the past decade have discovered deviating conclusions on what really causes the choking air pollution in Delhi. In 2003, the union Ministry of Environment and Forests published a white paper report that specifies in the three decades between 1970-71 and 2000-01, the contribution of vehicles to particulate matter in Delhi’s air had more than trebled to 72% from 23%. Therefore, vehicular pollution and road dust have emerged as major contributors in polluting Delhi’s air the most although the government studies have varying conclusion on the contribution of sources of particulate matter in Delhi’s air. Here are four major studies and the conclusion:
IIT-Delhi (February 2007)
In 2007, three years befor the Commonwealth Games (Delhi hosted) the Delhi government was worried about the huge increase in the number of vehicles plying in the city. According to the study, “Vehicles… in Delhi increased phenomenally from 2.3 million in 1975 (MOEF, 1997) to 4.2 million in 2004, [and] has been estimated [to go up to] 7.2 million in 2016 on the basis of transport data obtained from Transport Department, 2004.” And the conclusing states that, “control on emissions of pollutants from vehicular traffic necessitates the control on the new registration of commercial diesel vehicles in Delhi.”
NEERI, Nagpur (December 2008)
In 2008, Central Pollution Control Board (CPCB) with National Environmental Engineering Research Institute (NEERI) conducted a study for “better understanding” of air pollution sources was “recognised” in the Auto-Fuel Policy Document, 2002. As per the study, “With this in view, oil companies in India, in association with premier research institutions, joined together with the stewardship of CPCB and MOEF to initiate a detailed study for source apportionment of ambient air pollutants.” The closure report says that road dust as the biggest contributor (52.5%) to particulate matter in Delhi’s air, followed by industries (22.1%). It also added that “maximum vehicular pollution and road dust generation is estimated in the nearby area of India Gate.”
System of Air quality Forecasting and Research (SAFAR) project was developed for air quality forecasting during the 2010 Commonwealth Games. The report published on 2011 that nvolved detailed activity data for the region “using Geographical Information System (GIS) technique”. As per the “surprising” conclusion, the road dust from paved and unpaved roads contributed the largest share to air pollution (55%), followed by residential sources (15%), transport and vehicular pollution (13%), industrial sources (12%), and power (5%).
IIT-Kanpur (January 2016)
This IIT-Kanpur study in January 2016 had five major components – air quality measurements, emission inventory, air quality modelling, control options and an action plan. It carried out sampling during the winter of 2013-14 and the summer of 2014. The study reached out with the coclusion that unlike the 2008 and 2011 studies, this study, while underlining the role of road dust, also stressed on vehicular emissions — moving vehicles, in fact, contributed to over half of Delhi’s air pollution.