Singapore, Sep 15 (IANS) Air quality in Singapore crossed the "unhealthy" line Monday morning, as the three-hour pollutant standards index (PSI) reached 113 at around 6 a.m. And by 7 a.m. fell slightly to 111.

A PSI reading of 0-50 is considered "good", 51-100 is classified as "moderate", and 101-200 is ranked as "unhealthy", Xinhua reported.

The National Environment Agency (NEA) on its website advised people to reduce prolonged or strenuous outdoor physical exertion.

Singapore's air pollution index soared to a record high in June last year, mainly pushed by the transboundary haze resulting from forest fires in neighbouring Indonesia. To counter the situation, Singapore's parliament passed the Transboundary Haze Pollution Bill last month, paving the way to impose fines on companies whose actions elsewhere cause or contribute to transboundary haze pollution within Singapore.

The bill allows authorities to impose fines of up to 2 million Singapore dollars ($1.6 million) on companies that violate the law.