The correct options are
A Because of high deforestation in cities
C Because of the increase in population
D Because of the decrease in groundwater level in the city area
Trees help in bringing rain. If there are no trees, or if the area is deserted, then there is less chance of precipitation in the region. Air pollution contaminates rainwater to some extent, but it doesn't decrease the amount of water. Cutting trees for putting up industries, the high population of cities, and increased demand for water leads to water scarcity. The stock of groundwater is coming to an end.