North India emerged as the most-polluted region in the country in summers this year with Delhi-NCR being the hotspot, according to a new analysis by the Centre for Science and Environment (CSE).
The green think-tank said the average PM2.5 concentration in north India in summers stood at 71 microgram per cubic metre.
It was 69 microgram per cubic metre in east India, 54 microgram per cubic metre in west India, and 46 microgram per cubic metre in central India, it said.
Northeast India (35 microgram per cubic metre) and South India (31 microgram per cubic metre) were cleaner compared to other regions, it said.
In north India, Delhi-NCR was found to be the most-polluted sub-region, with Bhiwadi reporting the highest average PM2.5 concentration of 134 microgram per cubic metre.
Manesar reported average PM2.5 concentration of 119 microgram per cubic metre, Ghaziabad (101 microgram per cubic metre), Delhi (97 microgram per cubic metre), Gurugram (94 microgram per cubic metre) and Noida (80 microgram per cubic metre), it said.
PM2.5 summer average of the Delhi-NCR region is almost three times the average of the cities in southern India.
The CSE used granular real-time data from the Central Pollution Control Board's portal -- Central Control Room for Air Quality Management for the analysis.
The data is captured from 356 official stations under the Continuous Ambient Air Quality Monitoring System (CAAQMS) spread across 174 cities in 26 states and Union territories.