The air we breathe is laced with cancer-causing substances and is being officially classified as carcinogenic to humans, the World Health Organisation's cancer agency recently reported the issue.
The International Agency for Research on Cancer (IARC) cited data indicating that in 2010, 223,000 deaths from lung cancer worldwide resulted from air pollution and said there was also convincing evidence it increases the risk of bladder cancer.
South Asia that includes Bangladesh has a relatively high exposure.
Air pollution, mostly caused by transport, power generation, industrial or agricultural emissions and residential heating and cooking, is already known to raise risks for a wide range of illnesses including respiratory and heart diseases.
Research suggests that exposure levels have risen significantly in some parts of the world, particularly countries with large populations going through rapid industrialisation, such as China.
IARC reviewed thousands of studies on air pollution tracking populations over decades and other research such as those in which mice exposed to polluted air experienced increased numbers of lung tumors.
The agency said both air pollution and particulate matter — a major component of it — would now be classified among its Group 1 human carcinogens. That ranks them alongside more than 100 other known cancer-causing substances in IARC's Group 1, including asbestos, plutonium, silica dust, ultraviolet radiation and tobacco smoke.