While the Delhi government is considering installing outdoor air purifiers at traffic intersections, it turns out that the last time the city experimented with such a project, it was left hanging for five years.
The New Delhi Municipal Council had set up an air filtering station in 2010, before the Commonwealth Games.
The purifier was installed outside Palika Bazaar in Connaught Place free of cost by a company called System Life on March 6, 2010. The machine cleaned 10,000 cubic metres of air every hour for about 18 months. The system worked by cleaning polluted air of particulate matter and gases with fabric filters, active carbon cartridges and electrostatic filters.
According to System Life India director Dhruv Chanana, the machine was operational till October 18, 2011, before being removed. “It was removed because no one wanted to accept the need to clean the air,” said Mr. Chanana, adding that had the NDMC gone ahead with more such purifiers, the pollution levels in the area would have reduced. That being said, the authorities have remained mum on the effectiveness of such a project.
Dr. P.K. Sharma, NDMC’s Medical Officer of Health, said it was a pilot project and had not received the necessary approvals to continue. “It was a free demonstration by the company. Before continuing with the project, it required clearance of the Central Pollution Control Board and the Delhi Pollution Control Committee. We are yet to receive that,” said Dr. Sharma.
The air samples from the trial were analysed by three Italian scientists, including from the University of Modena. Their report was submitted to the NDMC and subsequently to the DPCC.
According to the report, a copy of which is with The Hindu , a total of 2.12 kg of particulate matter had been detained in 860 hours and the filtering efficiency of the system was 95 per cent.
The report concluded that with an “appropriate number of systems” (about 22 for Connaught Place) the air quality of an area could improve.
The DPCC, which works under the Delhi government’s Environment and Forest Department, for its part, did not make any comments on the efficiency of the system, as per a letter sent by one of its scientists to System Life on October 12, 2010. According to the letter, a copy of which is with The Hindu , the DPCC had not commented on the report “as no specific study was undertaken” by it.
Environmentalists, however, used the experience of the NDMC project to question the AAP government’s proposal to install outdoor air purifiers. Anumita Roychowdhury, the head of the Centre for Science and Environment’s air pollution and clean transportation programme, said air purifiers worked within confined environments, “but outdoor air is a complex chemistry with dynamic movement pattern”.