Kolkata air cleaner

Two-stroke autorickshaw ban shows results

By J Basu
Published: Sunday 31 January 2010

residents of Kolkata are breathing cleaner air this year¤ according to recent findings of the West Bengal state pollution control board (spcb). The high court order banning two-stroke autorickshaws and old commercial vehicles is said to be the reason for reduction in air pollution in the city.

The court order of July 18¤ 2008 was made effective from August 1¤ 2009.

Data generated by the automatic pollution monitoring station near the Victoria Memorial museum showed that benzene¤ carbon monoxide (CO) and nitrogen oxide (NO x) levels in November 2009 were much lower than the levels recorded in 2008 (see box). All the three pollutants are predominantly linked to automobile emissions. The findings have been submitted in the high court.

Dipak Chakraborty¤ chief scientist with spcb¤ said the lower level of benzene in the city air can definitely be linked to phasing out of two-stroke autorickshaws that used adulterated fuel called katatel¤ a toxic mixture of petrol¤ kerosene¤ naphtha ¤ benzene and other solvents. “The high court order has arrested pollution. NO x is emitted by diesel vehicles and its reduction can be attributed to phasing out of old taxis¤ buses and other commercial vehicles¤” said Biswajit Mukherjee¤ chief law officer of the state environment department. He said the new four-stroke-autorickshaws plying on city roads burn fuel more efficiently and release less CO.

Pollution under control  
Benzene (μg/m3) Nov 2008 Nov 2009 Standard
CO (mg/m3) 19.3 2 5
NOx (μg/m3) 3.2 2.2 2
(August-November) 90 75 80

Sources in Bajaj Auto Ltd¤ who are supplying the four-stroke autos¤ said about 10¤000 of the 25¤000 autorickshaws in the city core (Kolkata municipal area) have switched to four-stroke engines in the past one year. About 68¤000 autos ply within greater Kolkata including 30¤000 unauthorized ones which attract the court ban.

Environmental activist Subhas Dutta on whose petition the high court had passed the ban order said the court directives have been implemented only within the core city and not in the rest of Kolkata. “If reduction in pollution can be achieved by partially implementing the ban¤ think how much cleaner the air would be if the order is implemented fully¤” said Dutta.

The level of respirable suspended particulate matter in the city¤ however¤ remains unchanged due to growth in the number of vehicles.

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