HAKA: Delhi’s air has again made headlines for the wrong reasons. The US embassy’s pollution monitor at Chanakyapuri on Wednesday measured air quality at ‘very unhealthy’ levels, prompting a post in an international news portal warning against letting children outdoors for prolonged periods in the capital.

The embassy’s website calculated the air quality index (AQI) at 248 at 8am and 260 at 6pm. The index is a measure of air quality on a progressively deteriorating scale of 0 to 500, based on fine particulate matter (PM2.5) in the air, reports The Times of India.

According to US standards, readings in the 201-300 range are termed ‘very unhealthy’, which could lead to ‘significant aggravation of heart or lung disease and... significant increase in respiratory effects’.

The advisory for this level asks people with heart or lung disease, older adults and children to ‘avoid all physical activity outdoors’.

The embassy releases hourly AQI figures. Wednesday’s levels suddenly made news when a blog in the Wall Street Journal website quoted the figures. Ironically, it came on a day when air pollution in the city was at its lowest since Diwali and lower than the corresponding period last year.

Met department and earth sciences ministry air monitors showed only a slight different AQI level on Wednesday — an average of 220 for the day — but pegged the air quality level as ‘poor’. That’s because the ministry has a more relaxed categorization.

BDST: 1709 HRS, OCT 30, 2014