Thick black smoke emitted by nearly 1.5 lakh old and junk vehicles is causing serious environmental hazards for Dhaka.
Nearly 50 percent of vehicles plying the roads in the capital do not have fitness certificates, a senior official of Bangladesh Road Transport Authority (BRTA) told BSS.
The owners of unfit vehicles manage to receive certificates from BRTA with the connivance of a section of dishonest officials, sources said.
With the population growing in the city, motorised vehicles are also on the rise. It is estimated that about 100 used or new vehicles hit the road every day where road space covers only about six percent of city area.
At present, more than 3.2 lakh motor vehicles ply the roads in Dhaka city. Besides, overloaded, poorly maintained and very old trucks and mini-buses are also plying the city streets emitting black smokes and gases.
About 90 percent of these vehicles are faulty and emit smoke far exceeding the prescribed limit. Diesel vehicles emit black smoke, which contain unburned fine carbon particles.
Diesel-run vehicles account for more than 80 percent of the air pollution in Dhaka as most of them fail to comply with the approved emission standard, said a recently published survey report.
Air pollution levels in Dhaka are considerably higher than the limit mentioned in the World Health Organisation (WHO) guidelines for residential areas.
According to a study of WHO, blood lead level above 10 g/dl (microgram per deciliter) is considered to be a case of lead poison.
However, the lead level in the country's urban children was 5.8 to 21.6 g/dl, and the urban slum children's lead level ranged from 9.6 to 38.9 g/dl -- three times more than the acceptable level.
According to a World Bank report, Air pollution kills 15,000 Bangladeshis each year.
The report says the country could save between US $ 200 million and 800 million a year -- about 0.7 to 3.0 percent of its gross national product -- if air pollution in its four major cities can be reduced.
The report adds that 6.5 million people in these cities suffer from diseases each year. And the major disease is not diarrhoea, as is the popular perception, but acute respiratory infections caused mainly by polluted air. Automobile and industrial emissions, bad civic practices and poor government services are some of the major factors causing air pollution.
Greater exposure to particulates has been linked to premature deaths from respiratory and cardio-vascular illnesses, and higher rates of sickness, especially bronchitis and other chronic obstructive pulmonary diseases, as well as respiratory tract infections.
Other physical impacts of air pollution include damages to crops and ecosystems, degraded visibility, soiling of buildings, and damage to water quality through deposition of lead and other pollutants.
These effects on the ecosystem impair people's livelihood as well as health.
A large number of pedestrians, drivers, passengers, traffic policemen, street vendors and other groups undoubtedly suffer from significant health damage as a result of exposure to emissions from a large variety of motorised vehicles.
Experts attributed the air pollution mainly to vehicular emission. Thousands of vehicles ply the city streets without fitness certificates turning the metropolis into a virtual gas chamber.
"When particulate matters fall on earth or wetlands, they get absorbed quickly. But when these matters fall on concrete, vehicular movements make them airborne and the respiratory system of every individual, particularly children and women, bears the brunt," Prof Shahnaz Huq Hussain, dean of the Faculty of Earth and Environmental Science of Dhaka University noted.
It was reported recently that Dhaka again became the worst air polluted city in the world. Mexico City and Mumbai used to be the two most air polluted cities followed by Dhaka. But Dhaka is back again on the number one position.