With summer coming and water-tables falling rapidly, the Centre is readying to build 235 water harvesting structures, including dams, in the Capital,from March this year. This will be part of the Rs 175 croreproject to work on 5,088 schemes of dif-ferent kinds all over the country. Alarmbells are ringing as a recent study showsthat in 300 districts of 18 states in thecountry, groundwater is available four ormore metres below the surface, a difficultsituation. The 'over-exploited' or 'dark'-groundwater deficient- blocks in thecountry have increased from 250 in 1985to 470 in 2003.