Regrettably, the quality of the Ganga's water at most places downstream of Uttarakhand is unfit even for irrigation or bathing, let alone drinking. The count of harmful organisms, including hazardous faecal bacteria, at many locations is more than 100 times the limit set by the government. The water's biochemical oxygen content, which is vital for the survival of aquatic wildlife, has dipped drastically. Consequently, some of the unique native species of the Ganga, such as the river dolphin, the river turtle and the gharial, have been pushed to the verge of extinction. The most serious cause of this is the presence of urban wastewater and untreated discharge from hundreds of chemical plants, textile mills, distilleries, slaughterhouses, tanneries, etc.
The key to cleansing the Ganga, therefore, lies not so much in cosmetic treatments - for example, developing its riverfront at important ghats on the lines of the Sabarmati riverfront in Gujarat - as in taking concrete measures to avert further degradation of water and push cleaner water into the river. This would require either the reduction of water diversion or the augmentation of the river's flow by bringing in water from other sources. In other words, some canals must go dry to fulfil Mr Modi's promise. There are real trade-offs to be made, and the government must not shy away from them. Moreover, discharge of untreated effluents or wastewater into the river should be ruthlessly curbed. Apart from that, the encroachment of riverbed should be stopped. This may call for enacting legislation to create a river regulation zone similar to the one for coastal regulation zones. All these actions will have major socio-religious and economic consequences. Mr Modi has taken on a challenge that will severely test his government's management skills.