> he air quality index in the city hit 500 – the highest the measurement will go and 100 times the limit deemed to be healthy by the World Health Organisation (

> he air quality index in the city hit 500 – the highest the measurement will go and 100 times the limit deemed to be healthy by the World Health Organisation (WHO) From airnow.gov Daily AQI Color Levels of Concern Values of Index Green Good 0 to 50 Yellow Moderate 51 to 100 Orange Unhealthy for Sensitive Groups 101 to 150 Red Unhealthy 151 to 200 So it is 10 times the recommendation