August 19, when the Telangana government conducted the intensive household survey, was among the days when the city's air was least polluted, data from the Andhra Pradesh Pollution Control Board shows.
Air quality measurements from the day show a huge decline in particulate matter smaller than 10 micrometers (PM 10) emitted by automobiles. PM 10 reading from Punjagutta junction, one of the most polluted areas in the city, showed a reading of 65.16 microgram per cubic meter against an average of 115 and 145 microgram per cubic meter in May and June respectively. Carbon monoxide, which is also part of vehicular exhaust, showed a reduction to 1.15 milligram per cubic meter as against the average 2.5 milligram per cubic meter at the junction.
PCB officials could not provide data for Khairatabad and Paradise but said the numbers from these two junctions would also be considerably smaller. In the absence of readily available data for July, August and September this year, officials are unable to say if August 19 was the least polluted day this year. However, they did not discount the possibility.
"As most people remained indoors and a curfew-like situation prevailed, the air quality was much higher. Vehicular pollution is a major cause for concern that can be addressed by judicious use of private vehicles," a senior official said.
