Based on the fact of annual rainfall and the availability of total water resources, India is considerably rich at the national level. However, due to the uneven distribution of the resources often causes regional and temporal shortages. Countries population has increased rapidly since its independence in 1947. Simultaneously, with the introduction of high yielding variety crops in agriculture, dependency on water has increased tremendously since the Green  Revolution in 1965. During the past few decades, India has also witnessed rapid industrialization and urbanization leading to high economic growth. Although with these advancements, India has become self-reliant in many aspects of food security and economic stability but on another side, there has been a major loss to natural resources like wildlife, forest, and shortage in water supply and its quality .
During the past decades, it has been observed per-capita availability of fresh water has decreased with the increasing population . Continuously increasing high water demand has put the country’s water resources are under significant pressure. Due to the lack of stringent law and improper implementation of the already established laws and regulations, almost 80 percent of the water supply to the municipalities flows back into the ecosystem as untreated wastewater, which is a critical environmental and health hazard
Background and Discussion:
Decreasing per-capita water availability and increasing pollution in fresh-water resources are huge challenges as India continues to grow economically. In urban areas especially, water resources are under significant pressure due to high water-demand patterns. The situation is worsening with rising demand due to increasing urbanization.
Central Pollution Control Board (CPCB) evaluated 152 STPs spread over 15 states in the country and has a total treatment capacity of 4716 MLD. The study revealed that the actual treatment capacity utilization is only 3126 MLD (66%). Out of the 152 STPs, 9 STPs are under construction, 30 STPs are non-operational and the performance of 28 STPs not satisfactory.
Out of the 152 STPs, the treated effluent from 49 STPs exceeds the BOD standards and with respect to COD, 07 STPs are violating the general standards of Discharge. In 2017 out of 18.6% of total treatment capacity, only 13.5% of sewage was effectively treated . The report also says that almost 80 percent of water supply to municipalities flows back into the ecosystem as untreated wastewater, which is a critical environmental and health hazard.