The city administration has expanded its controversial car-free day program from just once a month to twice monthly.

The Jakarta Environmental Management Board, or BPLHD, announced on Thursday that it had scaled back the ban on vehicles on the main Jalan Sudirman-Jalan Thamrin thoroughfare during the last Sunday of every month, but would now bar traffic from other parts of the city on the second Sunday of every month.

“We received many complaints from people whose activities were disrupted so we gave up and reduced [the closure] by two hours,” said BPLHD head Peni Susanti.

Speaking at a press conference to outline the changes, Peni said traffic would now be barred from Sudirman-Thamrin between 6 a.m. and noon, bringing forward the previous finishing time of 2 p.m.

On a rotational basis, the second Sunday of each month would see traffic restrictions enforced during the same hours in areas such as Jalan Rasuna Said in South Jakarta, the Kota area of West Jakarta, Jalan Danau Sunter in North Jakarta, Jalan Pramuka in East Jakarta and Jalan Soeprapto in Central Jakarta.

During the car-free days, only the TransJakarta busway would be allowed to use the main roadways, while other public transportation and private vehicles must use the slow lane.

Peni said the aim was to improve air quality by reducing pollution from traffic, and to encourage more efficient use of cars.

Air-quality evaluations conducted during car-free days have shown significant drops in pollutant concentration levels, with dust particles reduced by 34 percent, carbon monoxide by 67 percent and nitrogen monoxide by 80 percent.

“Those three parameters are the primary pollutants from motor vehicles,” Peni said. “Motor vehicles are still the biggest polluters in Jakarta.”

Slamet Daryoni, the interim director of the Jakarta branch of the Indonesian Forum for the Environment, or Walhi, however, said that the car-free day program was ineffective.

“It won’t solve the air pollution problems,” he said. “Maybe the air quality in the area where the program is conducted is clearer, but that can’t be the standard measurement for all areas in Jakarta.”

Slamet said it would be best if the city administration suspended the program temporarily to re-evaluate its effectiveness and better promote awareness among motorists.

“We need car-free days, but just with better management,” Slamet said.