Which of the following is/are the possible consequence/s of heavy sand mining in riverbeds? 1. Decreased salinity in the river 2. Pollution of groundwater 3. Lowering of the water-table Select the correct answer using the code given below :

The correct answer is B, 2 and 3 only. Heavy sand mining lowers the water table and exposes groundwater to pollution, but it does not reduce river salinity. Riverbed sand acts as a sponge and a filter: it stores water, recharges the aquifers along the river and cleans water as it seeps down. When large quantities are dug out, the riverbed is cut deeper, the river flows lower, and nearby wells and the water table drop. Removing the sand layer also takes away the natural filter, so pollutants and silt reach groundwater more easily, and in coastal stretches a deeper channel lets seawater push further upstream. That is why statement 1 is wrong: mining tends to increase, not decrease, salinity near river mouths. It also damages bridges and embankments and destroys habitat for fish and other river life. Option A is wrong because statement 1 is false. Option C is wrong because it includes statement 1 and leaves out statement 2. Option D is wrong because it includes statement 1. Exam tip: sand mining = lower water table, polluted groundwater, more saltwater intrusion; India regulates it under the Sustainable Sand Mining Management Guidelines, 2016.