The total suspended particulates such as dust, smoke, and carbon monoxide has exceeded critical levels. The construction sites scattered throughout the capital city also contribute particulates. Only recently did the Bangkok Metropolitan Administration impose a regulation requiring that uncompleted construction sites be covered with plastic sheets after completion of the day's work. The financial crisis that struck the country, however, means that many of these half-completed sites will continue to be covered for a long period to come. Heavy construction works for mass transit structures continue, nevertheless, to be the principle source of dust and noise pollution in major corners of the capital city.
Industrial emission is also one of the major source of air-pollution.
Despite the policy to encourage decentralization of industries to the outlying regions, a large number of factories are still located in Bangkok. The dissolved oxygen levels have fallen below the level that can support river organisms. The khlongs that once gave Bangkok the name 'Venice of the East' have become black and foul smelling and, in places, function as open sewage systems. The major causes are uncontrolled dumping of household and community waste into the khlongs and rivers, and lechates from cisterns that seep into the soil, groundwater, and waterways. By regulation, households have to dispose of residential wastewater into a septic tank located within the premises.