KUALA LUMPUR, March 17 (Xinhua) -- Malaysian authorities have completed the clean-up efforts in the 1.5 km stretch of a river which had been polluted with hazardous chemicals, officials said Sunday.

The area, the Pasir Gudang district in Malaysia's southern state of Johor, would still be monitored after nearly 3,000 people were affected due to a serious chemical pollution, according to state news agency Bernama.

"The 1.5 kilometer stretch of Sungai Kim Kim that was polluted has been cleaned up, but today we want to see what more 'touch up' is needed," said Malaysia's Minister of Energy, Technology, Science, Climate Change and Environment Yeo Bee Yin.

"Today can be said to be a day of monitoring. After that, then only we can look into what further action is needed," she said at the state disaster management committee operations room in Johor Baru, the state capital.

Yeo said 30 teams comprising of Environment and Chemistry Departments personnel were deployed to 30 schools around the affected area, to monitor the air quality by using gas detectors.

Pasir Gudang is an industrial area located near the state capital of Johor Baru that borders Singapore. There are several major factories in the area that are involved in petrochemicals, palm oil and other heavy industries.

The authorities closed 111 schools on Wednesday after students and members of the public were given treatment for exposure to chemicals, with symptoms including shortness of breath, nausea and vomiting.

When the incident broke out last week, authorities were forced to evacuate over 1,000 people, mostly school students, after chemicals were illegally dumped in a river in the area.