According to a $1990$ report,Delhi ranked $........$ among the $41$ most polluted cities in the world.

In which state/country are Ecosan toilets not found?

Which of the following is $NOT$ a bioindicator of water pollution?

$FOAM$ stands for $........$

What is the main difficulty in the transition to $CNG$?

List all the wastes that you generate at home,school,or during your trips to other places. Which could you very easily reduce? Which would be difficult or rather impossible to reduce?