JAKARTA, Indonesia -- Indonesia has nearly halved output at a major coal-fired power plant near the capital Jakarta after the city faced major pollution spikes in recent weeks, its operator told AFP Wednesday.

The reduction came a week before Indonesia hosted leaders from the Association of Southeast Asian Nations (ASEAN) and top officials from the United States, Japan, China and South Korea for summits tackling a spate of regional issues.

The megalopolis of about 30 million people topped global pollution rankings several times last month, according to Swiss-based air quality monitor IQAir, as a toxic smog crisis threatened to overshadow the meetings.

"Since 29 August, PLN IP (Indonesia Power) has lowered Suralaya coal-fired power plant's production by 1,600 megawatts... to contribute in improving Jakarta's air quality," said Irwan Edi Syahputra Lubis, general manager of the plant's operator.

He said the plant, on the western tip of Indonesia's most populous island Java around 100 kilometres (60 miles) from central Jakarta, would now operate to produce 1,800 megawatts.

The official would not confirm how long the power cut would be maintained or if it was a permanent move, saying the firm would follow directives from the Indonesian government.

Indonesia has pledged to stop building new coal-fired power plants from 2023 and to be carbon neutral by 2050.

However, despite an outcry from environmental activists, the Suralaya coal plant on Java island is still being expanded to host 10 units within the plant's complex.

As public criticism has mounted over worsening air quality, Indonesia has responded by sanctioning 11 industrial firms for failing to meet operational standards and ordered half its civil servants to work from home.

The government had blamed weather patterns and vehicle emissions for the spike but some ministers have recently acknowledged coal-fired power plants and factories around the capital were also partly responsible.