They also said leakage of waste water from trucks that collect rubbish from septic tanks in the city pollute the environment.

Additionally, waste collection points are often overloaded with different types of rubbish. Meanwhile, rubbish is often held at collection points for an entire day before being removed to garbage dumps, spreading offensive odors throughout surrounding areas.

According to figures from the municipal Environmental Police Office, the Nam Son Waste Treatment Complex in suburban Soc Son District receives more than 4,000 tonnes of rubbish each day, transported by nearly 500 trucks, which is five times higher than its capacity.

With such a large amount of rubbish, waste collection trucks are often overloaded and have quickly deteriorated, resulting in waste water and rubbish falling from the trucks and onto roads.

Hoang Thu Phuong, a resident in Bach Khoa Ward, Hai Ba Trung District, said her house was near a waste gathering point and suffered from offensive smells throughout the day.

"Dustbins are overloaded, so many people have to place their rubbish on the pavement next to the dustbins, causing environmental pollution," she said.

"The smell from the waste becomes even worse during the hot weather when the rubbish is gathered there and removed by trucks only once a day in the evening," she added.

"Sometimes, waste water from trucks that transport rubbish to garbage dumps leaks onto roads," she added.

Deputy head of the Ha Noi Police's Environment Police Office Tran Quoc Dung told Suc Khoe va Doi Song (Health and Life) newspaper that many waste collection trucks failed to meet existing standards, leading to the leakage of waste water on roads, a situation that has existed for many years.

Under the current regulations, waste water needed to be carefully collected and waste collection trucks were specially designed with a system of drainage to contain waste water from rubbish.

However, many trucks have deteriorated and the system of drainage has broken down, causing waste water from rubbish to leak onto roads, polluting the environment, he said.

To solve the problem, he suggested waste collection companies provide regular maintenance for their trucks and alter waste collection methods and times so as not to have an impact upon local residents.

Dustbins at waste gathering points should also be carefully covered to not affect the surrounding environment, he added.

Further, environmental police could increase inspections to prevent sub-standard trucks from transporting rubbish on roads, he said.