Read the following text and fill in each gap with a suitable word based on the information of the text:

Air pollution comes from a wide variety of sources. In Bangladesh poisonous exhausts from industrial plants, brick kilns, old or poorly serviced vehicles and dust from roads and construction sites are some of the major sources of air pollution. We can minimise this type of pollution by making less use of motor vehicles and avoiding the use of vehicles older than 20 years. We may also use proper lubricants to lessen the level of emission and pollutants. We can encourage people to use Compressed Natural Gas (CNG) or Liquid Petroleum Gas (LPG) for fuelling their cars. The government may relocate hazardous industries like brick kilns to areas away from human habitations. 

Air is the most important element of human environment. Man cannot (a) ______ a single moment without air.  But (b) _____ do not think that it is (c) _____ who pollute this most vital element. (d) _______ the prevention of air pollution we (e) ______ avoid the use of vehicles older than 20 years.