Air quality data from the Maharashtra Pollution Control Board (MPCB) in the past decade shows that annual nitrogen oxide (NOx) concentrations in Mumbai was in the range of 60-80µg/m3, which is almost double the annual standard (40µg/m3). Mumbaikars were also exposed to annual concentrations of respirable suspended particulate matter (RSPM) two to three times the acceptable levels between 2004 and 2014. Worse, these were the MPCB’s conclusions after measuring pollution at just two spots — Sion and Bandra. Air pollution is also monitored by the Brihanmumbai Municipal Corporation (BMC) at Andheri, Borivali, Maravli (Chembur), Deonar, Bhandup and Worli and by the National Environmental Engineering Research Institute (NEERI) at Worli and Parel. However, the manner in which data is recorded by the agencies casts serious doubts over its accuracy. BMC has no data on pollution from May to December 2013 While shifting offices from Khar to Santacruz, BMC’s environment department did not monitor air pollution for around five months during the monsoon in 2013. “If we only reported the pollution levels averaged over eight months, it would show high pollution. In the monsoon, pollution gets washed out and since we did not have the data, we did not submit it for the entire year, to avoid errors,” admits an official from the BMC’s environment department. No monitoring in some areas In Borivali and around the hazardous dumping ground at Deonar, where garbage fires are a regular feature, there has been no air pollution monitoring since May 2013 owing to a paucity of lab assistants and a leopard scare in the area. “As we have an air pollution monitoring van frequenting Deonar dumping ground, we did not concentrate on fixed air pollution monitoring there. However, we have begun monitoring Deonar pollution in the last two months. At Borivali, we did not send our staff because of the leopard problem. We need to take 104 samples in a year, so we concentrate on locations where we can manage to get the data regularly,” says the official. No historical data at worst spots Around the industrial area of Maravli and at Deonar, air quality data from before 2007 is not available. Incredibly, the files were misplaced. “Storage became a problem while shifting offices and some files were misplaced. We now try to store the pollution data on computers,” says the official. Dysfunctional monitoring station The MPCB air quality monitoring station in Mulund has not been functional since April 2012. “The instruments had run their course and developed technical problems so we had to stop monitoring air pollution at Mulund,” says S C Kollur, Scientific Officer, MPCB. Other issues With the exception of Bandra, all air pollution monitoring stations are operated manually. Non-technical staff is trained to collect the filter papers, which are brought to BMC’s Santacruz lab, MPCB’s Mahape lab and NEERI’s Worli lab for analysis. NEERI’s scientists have also pointed out that locations of monitoring stations in the city are faulty. Indrani Gupta, senior principal scientist at NEERI, points out that monitoring stations for ambient air quality measurement should be 10 metres above the ground level. However, most monitoring stations in Mumbai are placed atop BMC ward offices and schools, much higher than the prescribed heights, she says. “Proximity to the highways and areas of heavy traffic congestion may influence the NOx levels in those regions. MPCB informed us that the monitoring station at Sion is right in front of the highway,” she says, adding that NEERI has advised the agencies to find better locations, “but nothing has changed”. The result of the multiple failures in data collection is that Mumbai has little scientific understanding of the historical trends and levels of air pollution. “For management purposes, the data is not enough. We need hourly monitoring to be able to gauge the actual pollution and suggest measures,” says Awkash Kumar from the Indian Institute of Technology- Bombay’s (IIT-B) Centre for Environmental Science and Engineering. Daily averages take into account pollution at night, which is low and also the time when a majority of the population is not exposed to air pollution, he explains. “We need to take into account the peak-hour pollution to really study the impacts of air pollution on Mumbaikars and to be able to suggest proper solutions,” adds Kumar. Alarm bells What will happen if the city continues to spew pollutants at this rate with no stringent measures or policies to curb air pollution? Emission levels would become highly unacceptable with regard to the particulate matter (PM) and NOx levels, especially if no control scenario continues till 2017, warns a study by NEERI. According to the Air Quality Assessment, Emission Inventory & Source Apportionment Study for Mumbai City by NEERI, by 2017, PM load will be high along the western part of Mumbai. In case of NOx in 2017, the concentrations will increase at industrial site and along the eastern and western corridors of Mumbai. In Mumbai, around 89.6 per cent of the people living in slums die of respiratory diseases, reveals a survey of slums in Mumbai by the International Institute for Population Sciences (IIPS) done this year.