The Comptroller and Auditor General (CAG) of India’s report on performance and audit on environmental degradation in the greater Guwahati area has shed new light on the mysterious smell that left the dwellers of Guwahati pass some sleepless nights. The familiar foul smell hit the panic button among the residents in the Noonmati area in the city on February 29, 2016. Such a foul smell, something like that of LPG, had created breathing problems among the residents in Nijarapar, Chandmari, Kharguli and Silpukhuri areas in the city on the night of February 19. The effect of the smell was so intense that people, who were fast asleep, felt difficulty in breathing. They came out of their houses in the open in large number and informed the police and fire brigade personnel for help. The police and fire brigade personnel did rush to the areas, but failed to find out the source of the smell. They had to patrol the areas throughout the night on February 19. Later the Kamrup(M) Deputy Commissioner did order an inquiry into the smell. The inquiry was conducted by a committee led by Guwahati Revenue Circle officer Lakshminandan Saharia. The committee comprised Pollution Control Board, Assam officials and police personnel as members. According to sources, the PCBA has failed to unearth the sources of the foul smell. The facts concerning the PCBA revealed by the CAG in its latest report have made it as clear as daylight the Board is unlikely to find out the reasons behind the foul smell as it has not been monitoring as many as nine of the twelve air pollutants notified by the Central Pollution Control Board (CPCB) for monitoring, thereby risking exposition of people and other wildlife in the State directly to air pollutants that could be detrimental to health. Who can say that the mysterious foul smell that had hit the panic button on the nights of February 19 and 29 would not be because of any of the nine air pollutants which the PCBA does not monitor? The PCBA was monitoring only three of the twelve air pollutants notified by the Central Pollution Control Board (CPCB) for monitoring. Besides, all monitoring stations were located in residential areas whereas there was no station in highly populated/vehicular density areas or in commercial, industrial and eco-sensitive areas. The CPCB had notified the National Ambient Air Quality Standard (NAAQS) in November 2009 with 12 identified pollutants, including gaseous pollutants – sulphur dioxide (SO2), nitrogen dioxide (NO2), ozone (O3), carbon monoxide (CO) and Ammonia (NH3); two dust-related parameters PM10 and PM 25; three metals lead, nickel and arsenic; and two organic pollutants benzene and BaP-particulate. However, the CAG report said that it had been found that the PCBA had been monitoring only sulphur dioxide, nitrogen dioxide and Respirable Suspended Particulate Matter (RSPM/PM10) and Suspened Particulate Matter (SPM) regularly at all the 22 locations. It was also observed during the audit that the PCBA had not carried out any study regarding effects of air pollution on human health in Guwahati city. If this is the reality, the prospect of the PCBA to unearth the gas that was behind the mysterious foul smell in the some city areas in February this year is bleak. It is worth mentioning here that the PCBA has been carrying out ambient air quality under the National Air Monitoring Programme (NAMP) since 1991, and till date in Assam there are 22 stations, including six in Guwahati. As per guidelines for Ambient Air Quality Monitoring, distribution of monitoring stations in a city depends on the distribution of pollution sources, and population in it. More stations should be located in areas according to population density, number of industries, and vehicular density. However, the physical verification of the six monitoring stations at Guwahati showed that all of them were located in places relatively with lesser population and vehicular density, the CAG report said.