Which one of the following is responsible for the sustenance of underground water?

Options

A. Loss of vegetation cover
B. Diversion for high water demanding crops
C. Pollution from urban wastes
D. Afforestation

Explanation

To determine which option is responsible for the sustenance of underground water, we can analyze each option provided:

1. **Laws of vegetation cover**: This option refers to the regulations or guidelines that protect plant life. While vegetation cover can influence water retention in the soil, it is not directly responsible for sustaining underground water.

2. **Diversion for high water demanding crops**: This option involves redirecting water resources to support crops that require a lot of water. This practice can lead to depletion of underground water sources rather than sustaining them.

3. **Pollution from urban waste**: Pollution can contaminate water sources, including underground water, leading to a reduction in water quality and availability. Thus, this option does not contribute to the sustenance of underground water.

4. **Afforestation**: This refers to the process of planting trees in an area where there was no previous tree cover. Afforestation helps in maintaining the water cycle, enhances groundwater recharge, and prevents soil erosion. By increasing vegetation cover, it allows more rainwater to infiltrate the ground, thus sustaining underground water levels.

After analyzing all the options, we can conclude that:

**The correct answer is D: Afforestation.**