Jakarta. Indonesian metropolis Jakarta becomes the world's sixth most polluted city as of 11 a.m. on Monday, according to IQAir's monitoring system.

Jakarta's air quality index at the time stood at 140. For reference, an air quality index of between 101-150 means that the air is unhealthy for sensitive groups. Jakarta is just behind India's Delhi (142). The world's top 3 most polluted cities are Baghdad (1,172), Brazil's Sao Paulo (222), and Pakistan's Karachi (162). Saudi Arabia's Riyadh recorded an air quality index of 161. A reading of beyond 301 points means that the air is hazardous.

The poor air quality prompted Jakarta's environmental agency to set up more monitoring stations, just like other major cities such as Bangkok and Paris.

"Bangkok has 1,000 air quality monitoring stations, while Paris has 400. We only have 111 of such stations, but this was quite an increase, as we used to have just five units. We plan to increase the number, so we can carry out faster and more accurate interventions," Asep Kuswanto, the head of Jakarta's environmental agency, was quoted as saying by the state-run news agency Antara.

According to Asep, data transparency is also key to improving Jakarta's air quality.

"So we can make sure that our measures are effective," Asep said.