However, in Coimbatore, there has been no specific study about the impact of pollution on the city’s residents, said environmentalist K Mohanraj. Apart from air pollution, vehicles also cause noise pollution. “The noise level can only be 60 decibels in residential areas. But most vehicles violate this norm,” he said.

The increase in numbers is worrying. “Around 1.1 lakh new vehicles are registered every year in Coimbatore. Like the city’s population, the number of vehicles per sq km is very high,” said K Kathirmathiyon, secretary, Coimbatore Consumer Cause.

“Most RTOs do not have the equipment to check vehicle emissions. If emission norms are properly implemented, most TNSTC buses would not be plying,” he added.

However, Regional Transport Officer (Coimbatore Central) S Munusamy said the department gets the work done by private parties. “It is true that we do not have the equipment to check emissions. The work has been outsourced. We have six emission testing centres for our RTO. Other RTOs in the city too have such centres who work for them,” he said.

Munusamy also denied that emissions from TNSTC buses were high. “The TNSTC’s maintenance team includes qualified engineers. If I find bus with high emissions I inform the TNSTC staff who take immediate action,” he said.

The Tamil Nadu Pollution Control Board has suggested several measures to check vehicular pollution, said K Ravichandran, District Environmental Engineer, TNPCB (Coimbatore South). Among them are use clean fuels like CNG and LPG and phasing out of old vehicles. Also, petroleum companies have been advised to introduce low-benzene petrol.

The smoke emitted by the ever growing number of vehicles, combined with the burning of waste in the open, are the major factors causing pollution in Coimbatore | Shankar NarayanMany admit that industrial pollution in the city is not so bad as it was a few years ago as most foundries have been moved to the Kurichi industrial cluster.

Mohanraj however cautions about other concerns. “It is true that foundries have been moved out. But there is gold recovery using mercury, which is illegal. Coimbatore’s water bodies are polluted with mercury, according to a study conducted a few years ago by the Salim Ali Centre for Ornithology and Natural History. The PCB has not done any study about this. I am sure the problem persists,” he said.

Pollution Levels have Declined in Kovai, Says TNPCB

Coimbatore’s rapid growth may give the impression of the city becoming more polluted by the day, but the level of pollution has actually come down, say TNPCB officials.

The city’s Comprehensive Environmental Pollution Index, which measures pollution levels, has fallen from 72.38 in 2009 to 53.14 in 2013. Indeed, in 2009, the Central Pollution Control Board (CPCB) had included Coimbatore among the country’s critically polluted cities and banned new industrial units and expansion of existing units.

The TNPCB drew up an action plan to control pollution. Effluent management and air-pollution control plants were made essential to get licences for industries. Continuous online monitoring of pollution levels was ordered. Based on these, the CPCB lifted the ban.

“We got almost all foundries in the city to shift to the Kurichi industrial cluster. Those still in the city limits have their own treatment plants,” said K Nalini, DEE, TNPCB, Coimbatore North.

Large industries (with gross fixed assets value of Rs 10 crore and above) have been asked to install online monitoring system for emissions. They are connected to the care air centres at the TNPCB’s Chennai head office and the emission levels monitored round the clock. If these exceed the prescribed limit, the staff are alerted, she added.

“We have opened bio-medical waste disposal centres and hospitals must tie-ups with them to get licences. We help local bodies to regulate solid waste disposal and guide them in identifying sites to dispose it. Burning waste in unsuitable places is an important cause of air pollution,” she said.

The CPCB has issued guidelines to the Transport Department, Traffic Commissioner, Railways, oil companies, etc, on reducing pollution, said K Ravichandran, DEE, Coimbatore South.

However, environmentalist K Mohanraj said most water bodies in the city remain polluted. “The Noyyal river and the Singanallur and Valankulam tanks are polluted with sewage. I am not sure about the groundwater,” he said.

But Ravichandran said water pollution too would soon be a thing of the past, informing that over 70 dyeing units have been closed to prevent water pollution