In a stinging remark on how the national capital monitors its air pollution quality, the Yale University on Wednesday said Delhi’s pollution data is not consistent or transparent, making direct comparison impossible.
The statement issued by the university in wake of a storm after its Environment Performance Index describing India as one of the worst-polluted countries in the world said the index was based on more reliable satellite data processed by a team of atmospheric chemists and remote sending experts.
"The data permit robust comparison across all nations. On such indicators, India has emerged as having air quality worse or as bad as China’s which fueled questions about how air quality compares in the two capital cities," the report the statement read.
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The latest national pollution data of over 280 cities across India is available till 2010 only.
Pollution watchdog, Central Pollution Control Board, which compiles the data from its own monitoring stations and those run by the state pollution control board accuses the states of delay in filing information about pollution data.
India does not have a national online mechanism where data collected by monitoring stations gets directly transmitted to a national server. The data is first scrutinised by scientists at various monitoring centers and state pollution boards before sending it CPCB, thereby raising a possibility of tampering.
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The daily average particulate matter 2.5 microns data for different locations in Delhi in the last few days, when pollution levels were high, has not been disclosed on the ground that it was under scrutiny.
On many locations where PM 2.5 microns is monitored on daily basis, the data for a longer period is not available on the respective websites of CPCB and Delhi Pollution Control Committee.
And this was precisely the issue raised by Yale University in its statement, which said Delhi was much behind Beijing in making air quality information available to its citizens.
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The lead author of the report Angel Hsu said there is no substitute for reliable, timely, local level air quality measurements.
"It is precisely the absence of a global network of such data that forces us to rely on satellite data," he added.
However, the scientists have questioned the use of satellite data to calculate PM 2.5 microns saying it can misleading as defining country specific or city specific boundaries become very difficult.