"Hazardous Substance" means any substance or preparation which, by reasons of its chemical

. "Hazardous Substance" means any substance or preparation which, by reasons of its chemical or physico-chemical properties or handling, is liable to cause harm to human beings, other living creatures, plants, micro-organism, property or environment. Environmental pollution means imbalance in environment. The materials or substances when after mixing in air, water or land alters their properties in such manner, that the very use of all or any of the air water and land by man and any other living organism becomes lethal and dangerous for health. POWERS OF THE SUPREME COURT The Act does not curtail the powers of the Supreme Court. It has from time to time in various matters issued directions and orders to control pollution. DIRECTIONS ISSUED TO CONTROL VEHICULAR POLLUTION In Mehta v Union of India 1999 in order to control the chaotic traffic conditions and vehicular pollution, the Supreme Court issued the following directions. (a) All commercial/transport vehicles which are more than 20 years old should be phased out and not permitted to ply in Delhi after October 1998 (b) All such commercial /transport vehicles which are 17 to 19 years old (3200) shall not be permitted to ply in the National Capital Territory, Delhi after 1998; (c) Such of the commercial /transport vehicles which are 15 and 16 years old (4962) shall not be permitted to ply after December 31, 1998 The Supreme Court made this order applicable to all commercial/transport vehicles whether registered in the National Capital Territory of Delhi or outside (but ply in Delhi) which are of more than stipulated age and which do not have any authority to ply in Delhi.