An important product in the ozone depletion by chlorofluorocabons is</h2></div>

There is a hole in the ozone layer. What do you understand by this?</h2></div>

During secondary treatment of primary effluent, how does significant decrease in BOD occur?</h2></div>

Number of ozone depleters identified by Viena convention for Protection of Ozone Layer (1992) is</h2></div>

Polluting strength of sewage is characterised by its</h2></div>

Ozone hole over Antarctica appear during</h2></div>

What is the major source of fresh water in the city/town/village? where can you live? Do you know of any activity which …

What happens if the forest area decreases rapidly ?<br> </h2></div>