KUALA LUMPUR, June 25 -- As students faced breathing issues and vomiting, some 400 schools in a state of Malaysia were closed.

The schools were closed in the Malaysian state of Johor after 75 students experienced breathing difficulties and vomiting.

Schools in the industrial area of Pasir Gudang have been shut until Thursday as authorities investigate the latest air pollution incident to hit the state.

In March about 4,000 people - mostly children - fell ill after chemical waste was illegally dumped in a river.

The closed schools include more than 100 primary and secondary schools as well as 300 private kindergartens.

Johor Chief Minister Dr Sahruddin Jamal said 75 students from 15 schools had complained of breathing difficulties and...