Cotton pollen grains are an important pollutant in which of the following cities?

The Taj Mahal is threatened due to the effect of:

Define $BOD$.

The dental disease characterized by mottling of teeth due to the presence of a specific chemical in drinking water is caused by which of the following elements?

According to the Euro-$II$ norms,which of the following is correct?

According to recent reports on acid rain,industrial cities are affected by atmospheric pollution due to which of the following?