The diesel-run vehicles, that were declared unfit back then are slowly making their way back on the city streets, are one of the main reasons for this deterioration of air quality, said officials at Department of Environment (DoE).

These unfit diesel-run vehicles are responsible for more than 70 percent of air pollution in the capital as they fail to comply with emission standards, added the officials.

A recent study conducted by Air Quality Monitoring Project (AQMP) of DoE revealed that the air in the city, affecting nearly 12 million inhabitants, fails to meet required health standards. The air quality, especially during the heavy traffic hours, is so poor that it falls below the legally permitted level of pollutants.

During the following week of banning the 2-stroke auto rickshaws in January 2003, presence of two of the major air pollutants -- particulate matters and hydrocarbon -- dropped significantly from city air. The particulate matters went down by around 41 percent while hydrocarbon by 52 percent, according to the DoE officials.

Both of these harmful elements as well as other pollutants have increased at an alarming rate during the recent times.

"Pulling the two-stroke auto rickshaws out [of the city] was a vital step taken by the government to improve the air quality in the city, and it also created a stir of awareness on this issue [air pollution]," said Hasib Hasan, enforcement officer at AQMP.

"However, it seems that the awareness was quite temporary as failure to ensure effective measures left room for the obsolete and unfit diesel-run vehicles to make a comeback on the streets," he added.

Vehicular emissions include pollutant elements such as particulate matter, hydrocarbons, nitrogen oxides, carbon monoxide and carbon dioxide. These are all potentially lethal and harmful to all forms of lives.

Zarif Mahmud, a service provider from Azimpur, was at Shahjahanpur intersection on his two-wheeled scooter waiting for the traffic lights to turn green. He was already late for work and was struggling to make his way through the Sunday morning rush hour traffic. As the vehicles began moving, he was engulfed by a gust of black smoke from a bus in front of him.

"My eyes began to sore and I started a coughing hysterically as I inhaled the toxic smoke," said Mahmud.

"I couldn't breathe properly for almost half a minute and coughed until my lungs cleared off the deadly smoke," he added.

At a time when cleansing drives in almost all aspects of urban life are being conducted by the present government, one would expect that the government would take a tough stand on resolving this issue of air pollution, Mahmud hoped.

Israt Jahan, a resident of Pallabi, said, "I have to face such situation almost everyday on my way to drop my daughter off at her school and also the way back home."

"The consequences of these nuisances are extremely harmful for me as I have severe respiratory problems. It feels as if I am being choked to death," complained Jahan.

The AQMP department of DoE has two mobile inspection teams consisting 8 members who are inspect vehicles for violation of emission standards.

Under the Act 150 of traffic law, traffic officials can fine an offender only Tk 200 for violating vehicular emission standards. However, as par the environment protection act, a magistrate can fine a first-time offender up to Tk 5,000. For second and third offences, the penalty could be Tk 10,000 and jail term respectively.

While diesel-run vehicles emit the most of air pollutants, other polluters of city air include brick kilns, diesel generators, plastic factories, open air burning of plastic items and foundries, said AQMP officials.

During winter, around 4,000 brick kilns surrounding the city play a major role in polluting the city air by emitting toxic smoke, the AQMP officials added.

According to Dr Mohammad Nasiruddin, director of AQMP and also deputy secretary of DoE, a sustainable coordination is required between different governmental departments to improve the overall situation.

"Definitely there is a lack of coordination and understanding between different departments such as DoE, BRTA [Bangladesh Road Transport Authority] and DMP [Dhaka Metropolitan Police]. Coordination of all these departments is necessary to make the situation better," Dr Nasiruddin added.

"However, as for short term measures, the government should ban the import of reconditioned vehicles, especially from India as they are currently going through a environmental revolution and are basically dumping all their substandard and unfit vehicles into our country," he observed.

Before two-stroke auto rickshaws were banned and CNG run vehicles were introduced in Dhaka in the year 2003, environmentalist organisations worldwide used to dub Dhaka as 'gas chamber'.