North India is most polluted with the Delhi-NCR region being a hotspot according to new data.
A national assessment by the Centre for Science and Environment (CSE) has put forth that the Particulate Matter2.5 average in the northern capital region is almost three times the average of cities in southern India.
While pollution this summer has been higher than pollution last summer; the highest daily peak of pollution has been recorded in cities of Bihar.
It is also interesting to note that it is not the mega cities which are most polluted but smaller cities have become pollution hotspots. Bhiwandi in Rajasthan tops the list.
The high level of summer pollution is the result of a combination of pollution from vehicles, industry, power plants, waste burning, and dust sources and wind-blown dust, aggravated by heat and arid conditions.
For the study, data from March 1 to May 31 has been considered. Besides the fact that Delhi-NCR is the most polluted, other major findings are that daily peak pollution was the highest in east India, with cities of Bihar recording the highest levels: Summer daily peak PM2.5 levels for east India stood at 168 µg/m³, the highest among all the regions. North India with 142 µg/m³ summer peak was the second worst. West India (106 µg/m³), central India (89 µg/m³), cortheast India (81 µg/m³) and south India (65 µg/m³) also recorded summer peak in excess of 60 µg/m. Within north India, Delhi NCR was found to be most polluted sub-region.
The cities of Bihar recorded very high summer PM2.5 averages, with Bihar Sharif reporting the highest summer peak of 285 µg/m³. Katihar (245 µg/m³) and Patna (200 µg/m³) also recorded peak level in excess of 200 µg/m³. Rohtak recorded the highest peak pollution in north India with a 258 µg/m³ daily peak.
Another key finding is that north India has recorded a staggering 23 per cent increase in seasonal PM2.5 level compared to the previous summer. Within north India, NCR was the worst performing sub-region with 25.8 per cent increase in seasonal PM2.5 level. Central India registered increase of 15.6 per cent while west India (4.2 per cent) and east India (1.8 per cent) registered increase under five per cent. South India showed no change in the seasonal average but saw a decline of 22 per cent in seasonal peak. Northeast India registered drop in both seasonal average (-12.8 per cent) and seasonal peak (-18.3 per cent). East India was the only region which registered an increase in its seasonal peak compared to last summer.
In south India, eight cities show an increasing trend. Kozhikode saw a jump of 76 per cent in summer average and 17 per cent increase in peak. Kochi has the most divergent trend with 55 per cent increase in the summer average but its peak increase by 145 per cent. Other cities with increasing trend in the region are Madikeri, Bengaluru, Puducherry, Amravati, Chikkaballapur, and Thiruvananthapuram.
“This analysis identifies the unique patterns of pollution across all regions and puts a spotlight on a large number of towns and cities that do not get policy attention. Summer particulate pollution spikes due to arid conditions, high summer heat and temperature, and more airborne dust particles that travel long distances compounding the problem from local sources,” said Anumita Roychowdhury, executive director, research and advocacy, CSE.
