The correct option is (d) 1, 2, 3 and 4.
Explanation
Water shortage refers to the lack of sufficient available water resources to meet the demands of water usage within a region. It is driven by both natural climatic factors (physical scarcity) and human activities (economic scarcity or qualitative degradation).
Statement-wise Analysis:
- Statement 1 is Correct: Variation in seasonal precipitation leads to temporary water stress. For instance, in regions dependent on monsoons, the dry season often witnesses acute water shortages due to the uneven temporal distribution of rainfall.
- Statement 2 is Correct: Variation in annual precipitation affects the long-term availability of water. Years with below-average rainfall (drought years) fail to replenish surface bodies and groundwater aquifers, causing shortages.
- Statement 3 is Correct: Over-exploitation of water sources occurs when water is withdrawn at a rate faster than its natural recharge. This is common in intensive agriculture and industrial zones, leading to falling water tables and the drying up of aquifers.
- Statement 4 is Correct: Contamination of water sources reduces the availability of usable water. Even if water is physically present, pollution from industrial effluents, sewage, or agricultural runoff can render it unfit for consumption or irrigation, effectively contributing to water shortage.
Key Takeaway:
Water shortage is not merely a function of low rainfall; it is equally caused by the mismanagement of existing resources (over-exploitation) and the degradation of water quality (pollution), which limits the supply of potable water.