In acid rain,$SO_2$ accounts for approximately what percentage (in $, \%$)?

Which of the following statements is/are correct?
$I.$ Chemical fertilizers cause pollution of water bodies as well as groundwater,besides getting stored in crop plants. Therefore,environmental scientists are pressing for a switch over to organic farming.
$II.$ Organic farming is a form of agriculture that relies on techniques such as crop rotation,green manure,compost,and biological pest control.

Which of the following are advantages of ecological sanitation?
$I.$ It is a practical,hygienic and efficient method of waste disposal
$II.$ It is cost effective
$III.$ Human excreta can be recycled into natural fertilisers,to replace chemical fertilisers

Soil conservation can be best achieved by having

In the $1990s$,Delhi ranked ............. among the ...... most polluted cities of the world.

Which act was enacted by the Government of India to protect and improve the quality of our environment and to control environmental pollution?