Which of the following options can help sustain underground water availability?

Reducing pollution from industrial effluents and wastes is the best option for sustaining underground water availability. This can be achieved by implementing better waste management practices, reducing the usage of harmful chemicals, and promoting sustainable industrial practices that minimize water usage and waste.

Dependence on suitable rainfall for cultivation is not a reliable method for sustaining underground water availability as rainfall is unpredictable and can vary greatly in different regions.

Increasing the loss of vegetation cover is not helpful in sustaining underground water availability, as vegetation plays a crucial role in retaining water in the soil and preventing soil erosion, which is essential for recharging the groundwater.

Diverting to high water-demanding crops can lead to excessive water usage, which can deplete the groundwater and reduce its availability in the long run.