One third of the population in the high-density Dhaka metro cannot rely on piped water, a new global report revealed on Wednesday.
Dhaka struggles to provide good living conditions to its residents for its inability to deal with waste.
It generates an estimated 5,000 tonnes of waste daily, but only half is properly collected and disposed of.
The city, combined with rapid urbanisation, is affected by ecological changes in several ways.
Meanwhile, Dhaka is among 20 most unsustainable megacities globally with poor living conditions, said the report styled 'Ecological Threat Report' produced by the Institute for Economics and Peace.
Eight cities in South Asia are among the world's 20 most unsustainable megacities. They are facing the highest population growth and worst vulnerability to ecological threats.
Dhaka has been one of the fastest-growing cities in the world as its population doubled from 6.0 million to 12 million between 1990 and 2005.
The city's population is further expected to increase to 35 million from its current population of 22.6 million, an increase of 53 per cent.
One reason for this growth is that approximately 2,000 people move to the city per day.
Dhaka covers an area of just 360-square kilometres with 22.6-million population and has become one of the denser cities globally (with 29,000 inhabitants per square kilometre), according to the report.
The city is impacted by regular floods, which are only likely to increase. As it is low-lying, it may be affected by sea level rises.
Even Dhaka has to cope with infrastructure problems particularly in transport, water, waste and energy.
Dhaka's rapid urbanisation highlights its central role in Bangladesh's drive to move from being a low-income to a middle-income country.
The city generates around one fifth of Bangladesh's total economic output and provides more than 40 per cent of its formal sector jobs.
The report tracks the links between climate change, ecological threats and violent conflict or forced migration each year.
Dhaka, Lahore, Kolkata, Delhi, Karachi, Mumbai, Chennai and Hyderabad are eight of the 20 cities facing the highest population growth and worst vulnerability to ecological threats.