The number of people suffering from diarrhoea is increasing day by day because the Water and Sewerage Authority (Wasa) is continuing to supply polluted water to Dhaka residents.
Eighty percent of patients at the International Centre for Diarrhoeal Diseases and Research, Bangladesh (ICDDR,B) reported that the drinking water supplied by Wasa is foul smelling and dirty.
Each day more than 800 patients seek treatment at the ICDDR,B.
In the last fortnight, the number of patients being admitted each day has increased by around 30 percent.
The majority of patients requiring treatment at the ICDDR,B are from the capital's Mirpur, Khilkhet, Demra, Badda, Wirelessgate, Rampura areas, as well as Pagla in Narayanganj.
Shahjahan Siraj, a resident of Mirpur, Sheorapara, said, "Our water has been smelly and dirty for the last month.
"Even boiling it fails to remove the odour.
"This is not only my complaint -- my neighbours are also suffering."
Babul from Khilkhet also complained of foul smelling water in his locality for the last two months.
Doctors have said that water and sanitation systems in the capital must be improved.
Scientist and Head of Longer Stay Unit of ICDDR,B Dr Shahadat Hossain said, "Around this time of year it is common for a significant number of people to suffer from diarrhoeal diseases.
"However the situation this year goes beyond the usual phenomenon.
"If the government doesn't take the issue seriously, the situation will continue to worsen," he warned.
Dr Hossain said that patient records at ICDDR,B indicate that the number of people suffering from diarreaoh has increased year on year.
On average, around 8,877 patients visited the ICDDR,B every month in 2006, which increased to 10,177 in 2007.
In 2008 the number of patients rose to 10,182 and in 2009 some 11,601 patients visited the hospital.
This year the monthly average of patients stood at 10,800.
Dr Shahadat attributed the increase partly to a rising population in Dhaka, but said that the government has failed to ensure that residents have access to safe drinking water and proper sanitation systems.
He added, "Even those who are willing to boil water find it very difficult because of frequent loadshedding and the gas crisis.
"It is a vicious cycle."
Quoting laboratory reports, scientists from ICDDR,B said that 40 percent of patients are suffering from cholera and that most patients are from a lower socio-economic group.
A study conducted by ICDDR,B in the capital's Badda area last year revealed the presence of the vibrio cholerae bacteria which is responsible for cholera.
Dr Shahadat said, "Eighty percent of the water samples from the locality contained cholera.
"The situation is similar in other parts of the city."
A large number of residents from West Sheorapara said that Wasa has been supplying foul-smelling and dirty water for the last six weeks.
All residents have had at least one family member who has suffered from diarrhoea during this time.
An aggrieved local said there is little point in lodging a complaint with Wasa, which has seemingly remained indifferent despite a High Court order to improve the quality of its services.
Managing Director of Wasa Taksin A Khan has acknowledged that the water supplied by Wasa is foul-smelling in many areas.
He said, "The water smells because the Shitalakhya River is very polluted.
"We are yet to build a new treatment plant, so we have been using an excessive amount of chemicals to treat the water."
However Khan maintains that the issue of poor quality water is no more severe than in previous years.
He added that just 13 percent of the water supplied by Wasa is sourced from the polluted river.
"If the water supplied by Wasa was polluted we would be experiencing a diarrhoea epidemic," he said.
Khan believes that the majority of people suffering from diarrhoea are slum dwellers that have accessed the water using illegal rubber pipelines.
He said that Wasa and NGOs are working together to provide safe drinking water to slum dwellers.