Figure 2 : Proportion of sewage disposal directly to the rivers in different states of India                                                                             (Source: Kumar, 2021)
From the data obtained from the Central Pollution Control Board, India, it can be concluded that there is still lacking in the implementation of the laws or regulations in the Indian context. The disposition of sewage is associated with heavy metal contamination as we have apprehended from the above sections. Thus, in the next part, we will mostly cover the effects of heavy metals found in sewage and the pollution caused by them. Heavy metal pollution has been a serious environmental concern in river basins for the last 40 years, and extensive research has been conducted to demonstrate the sources, diffusion, and destiny of the pollutants, as well as the accompanying interactions with civilization. The worldwide number of heavy metals discharged into the environment in the final half of the twentieth century was 22,000 tonnes of Cd, 939,000 tonnes of Cu, 783,000 tonnes of Pb, and 1,350,000 tonnes of Zn (Sharma 2011). Heavy metals, due to their solubility, may be spread by water and, as a result, harm aquatic habitats. (Masindi & Muedi 2018). In 2006, the dissolved metal content in the Buriganga River (Bangladesh) was 126 ppm of Cd, 805 ppm of Pb, 5,274 ppm of Cr, and 595 ppm of As (Bhuiyan et al. 2015). Such high amounts of heavy metals in surface water are a direct hazard to human health and necessitate immediate action as well as more investigation (Siddiqui & Pandey, 2019). In the case of Indian rivers, the Ganga river contains the majority of heavy metal pollution. The next part will go through the present state of the situation.