Much of the drinking water in the eastern Indian city of Calcutta is contaminated with human excrement, according to a government ministry report.
By Subir Bhaumik
BBC correspondent in Calcutta
Calcutta's water infrastructure needs work
Although this is the seventh report on drinking water quality in Calcutta since 1985, experts say authorities have done little to improve hygiene.
The report was released this week by the Federation of Consumer Associations, or FCA, which undertook the study for the ministry for food and consumer affairs.
The FCA sampled water from nearly 1,000 locations in the city for its report.
Leaking sewage system
It found that 87% of water reservoirs serving residential buildings had high traces of human waste within them.
Water collected from 63% of taps showed a high level of faecal contamination, while 20% of water samples taken from the city's hospitals also turned out to be polluted.
Roughly one-fifth of the deep wells and hand pumps maintained by the Calcutta Municipal Corporation also had traces of excrement.
Dr K J Nath, a former director of the All India Institute of Public Health and Hygiene, told the BBC that the state government and municipal bodies did not consider providing clean drinking water a priority.
Dr Nath, who carried out the first survey into Calcutta's water quality in 1985, said a leaking sewage system and pressure variations in the city's water supply were to blame for the contamination.
The mayor of Calcutta, Subrata Mukherjee, said efforts were being made to identify parts of the city where water quality was particularly poor.