The addition of harmful and disadvantageous substance sot the natural reserves and resources of water is termed as water pollution. It can be in the form of flowing water like rivers, streams, oceans and seas or stagnant water bodies like lakes etc. Even the underground reserves of groundwater are affected by percolation of pollutants either through soil or surface run off.
Among various causes and sources of water pollution, the major one are industries who release their untreated or partially treated refuse called as effluents into the water bodies as dump or dispose.
This water may in turn reach seas and oceans and spread to a wider areas than initially assumed. The next big source is the domestic habitation near the river banks or coastal areas etc. The refuse and waste from these houses I often dumped into the adjoining water body. The dumping of dead bodies (as pr certain religions) or ashes also play a huge part in contamination of natural waters.
There are also activities like bathing, washing clothes etc which are performed in or near rivers further adding to their pollution. Even transportation though waters like ships etc, often causes spilling and accumulation of waste which can be catastrophic for the water and its quality.
The menace of water pollution can be tackled only by forming a multi pronged strategy. The basic issue is of awareness and education. People have to be trained and taught the that certain activities can not be allowed near water bodies and certain lifestyle changes are needed to be incorporated to arrest such form of pollution.
This needs to be backed by robust policy and stringent laws that penalize defaulter and polluters like big industries etc.
There has to development of infrastructure for holistic treatment and purification of water and also waste water (from various sources). Better methods of waste disposal especially industrial waste, radioactive waste etc have to be developed leveraging newer and environmentally sustainable technologies.
Apart from these there has to be overall focus on developing habits of conservation and reuse of water resources for them to be enjoyed for a long time to come.