Cleaning the river will not solve the problem of river pollution if the drains are dirty.

Universiti Sains Malaysia (USM) River Engineering and Urban Drainage Centre director, Dr Nor Azazi Zakaria said cleaning the river is actually cleaning the sea while cleaning the drains is actually cleaning the river as the water from the drains will flow to the river.

"We will always have a dirty river if we have a dirty drain which is full of rubbish and by cleaning the river will not solve the main problem,” he said during a forum titled "Clean Sungai Pinang, Stop Pollution at Its Source", here today.

Meanwhile, State Local Government, Traffic Management and Flood Mitigation Committee Chairman Chow Kon Yeow concurred with Azizi, adding that the main cause of pollution is the lack of civic consciousness among the people.

"The major cause of river pollution is rubbish waste from the locals and the problem will never be solved as long as the mentality of the people who treats the river as dumping site is not changed," he said.

After years of cleaning Sungai Pinang, which has been dubbed as the most polluted river in Penang, the water pollution level had improved from level four (extremely polluted) to level two (minimally polluted).

Currently, the river is between level three and level two and with the improvement in the water quality, otters had been spotted in the vicinity of Sungai Pinang which indicates the existence of marine lives.

The state is also targeting to achieve the 2A level of pollution index for Sungai Pinang by middle of next year.

Chow, however, conceded that maintaining the water level at 2A is going to be difficult if the mentality of the people does not change.

Northeast Drainage and Irrigation Department (DID) engineer Norhaslinda Hamran said that the department had installed a log boom and several other trash trappers at Jalan Sungai to capture the waste that flows in Sungai Pinang.

"In 2013, when the log boom was installed, it had captured some 15 tonnes of rubbish in a year but in 2015, some 45 tonnes of rubbish were captured in the log boom.

"This shows that the amount of rubbish thrown into the river had increased tremendously," she said.

The Sungai Pinang is 3.2kilometre long with 50.97 kilometere of catchment including several rivers such as Sungai Dondang, Sungai Air Itam, Sungai Air Putih, Sungai Air Terjun and Sungai Jelutong that flow into Sungai Pinang before flowing to the sea.

Besides rubbish dumping, the main factors contributing to pollution in Sungai Pinang were high density residential areas, restaurants and workshops that throw their daily sewage directly into the river and also industrial waste.

So far, the state government has spent more than RM3 million to improve the water quality of Sungai Pinang.