Answer: 

Groundwater is the water that seeps through aquifer rocks and soil and is stored below the ground. In India, groundwater accounts for about 40% of total water supply. Although invisible but it silently supports many activities like:

1. Agriculture: It supports irrigated agriculture (approx. 90%) and food security
2. Ecosystem: It replenishes lakes, rivers, and wetlands; and sustains plants, animals, and human lives.
3. Drinking water: It provides drinking water to 50% of the global population.
4. Industry: It is used in industrial processes where surface water is limited.

Reasons for alarming decline of groundwater:

1. Overexploitation leading to land subsidence and saltwater intrusion into coastal aquifers; it is often poorly understood, undervalued, mismanaged, and even abused.
2. Poor governance: It is not physically visible, making it difficult for the general population and decision-makers to connect with the challenges affecting this resource.
3. Urbanization: Rapid urbanization and population growth have increased demand for groundwater for drinking water supply and industrial purposes. Cities like Chennai and Bangalore face groundwater depletion due to excessive urban expansion.
4. Pollution: Surface water encroachment, scarcity, and pollution are easily visible. But there is hardly any visual evidence for groundwater facing the same challenges. 

Eg: Arsenic contamination in West Bengal. 

1. Neglect by public, CSO, media: Groundwater education is a neglected area, appreciation of groundwater is not taught in elementary schools. Thus, behavioural change is necessary to understand existing issues.

Ensuring sustainability of groundwater:

1. Aquifer mapping, real time monitoring of consumption, extraction and recharge. Government, media and civil society has important role in educating people about groundwater. 

Eg: Maharashtra and Andhra Pradesh have introduced groundwater regulation acts to address over-extraction.

1. Afforestation to increase residence time of rain water and rain-water harvesting techniques must be adopted for groundwater recharge.
2. Aquifers and groundwater reservoirs often extend beyond political boundaries of countries/states, so international/inter-state cooperation is also necessary.
3. Mihir Shah Committee (2016) proposed an effective groundwater governance structure:
4. The Central Water Commission and the Central Ground Water Board (CGWB) should be

united under a national water framework for an integrated approach.

1. Linking cropping patterns and crop intensity with groundwater availability.
2. Effective implementation of government initiatives like National Project on Aquifer Management (NAQUIM), ‘Catch the Rain’ campaign and Atal Bhujal Yojana is required for sustainable management along with community participation.

Groundwater depletion poses a significant challenge to water security and consequently to food security and sustainable development in India. By ensuring sustainable groundwater management, India can contribute to achieving Sustainable Development Goal 6 (Clean Water and Sanitation) and safeguarding this vital resource for future generations.