India is the largest and fastest consumer of groundwater, which fulfills the demands of nearly 80 and 50% of the rural and urban population, respectively (Shankar et al. 2011). The groundwater resources of the country are estimated to be 433 BCM, which is 39% of the total water resources of India (CGWB 2017). The net groundwater availability is 396 BCM, while the available for potential use is 245 BCM. The stage of groundwater development is 61% (CGWB 2017). The Indian state Uttar Pradesh has the highest net annual groundwater availability (~72 BCM) and Delhi has the least (0.29 BCM) (CGWB 2014). Around 85% of the rural population uses groundwater for drinking purposes. The volume of groundwater is inadequate to fulfill the demand of the large population, agricultural practices, rampant industrialization, and urbanization. The overall account of groundwater resources assessment 2004–2017 is presented in Table 1.3.
The per capita average water availability in India is continuously decreasing. India has a huge potential in river and precipitation water (rainfall+snowfall), but currently, not even 50% of the potential is being used. Due to the lack of use of the water potential of river and precipitation, groundwater resources are under tremendous pressure and the water table is continuously increasing in most parts of the country over time.
Table 1.3 Groundwater resources assessment from 2004–2017.
Source: CGWB (2017).
| Year | Annual replenishable groundwater resources (BCM) | Net annual groundwater availability (BCM) | Annual groundwater draft for irrigation, domestic, and industrial uses (BCM) | Stage of groundwater development |
|---|---|---|---|---|
| 2004 | 433 | 399 | 231 | 58% |
| 2009 | 431 | 396 | 243 | 61% |
| 2011 | 433 | 398 | 245 | 62% |
| 2013 | 447 | 411 | 253 | 62% |
| 2017 | 432 | 393 | 249 | 63% |
1.3 Quality of Available Water Resources in India
Water quality of both available surface and groundwater resources does not satisfy the criteria for potable water in most parts of the country. The Ministry of Jal Shakti report revealed that 70% of water resources in India are polluted by untreated sewage and industrial effluents. The monitoring report of the Central Pollution Control Board (CPCB 2011), based on biological oxygen demand (BOD) and coliform bacteria count, indicated that organic pollution is predominant in aquatic bodies. The groundwater of around 600 districts (i.e. almost one‐third of India) is nonpotable. On the other hand, the Central Groundwater Water Board (CGWB) has reported the presence of contaminants like fluoride, nitrate, arsenic, iron, and other heavy metals in the groundwater of many regions (Table 1.4). As and F− contamination of groundwater is a significant public health risk concern for Indian people. As and F− contamination of groundwater is a health threat for approximately 100 and 66 million Indian people, respectively (Bindal and Singh 2019; Kadam et al. 2020). Other major groundwater contaminants like U, NO3−, Fe, HCO3−, etc. have also been reported in several parts of India. High nitrate content in water is another grave concern in many states (Ministry of Water Resources 2014;
