Environment experts have warned that the Air Quality Index (AQI) of Indian capital, Delhi has reached 'critical' level mainly due to the increased presence of dust and heat.

The data showed that the Air Quality Index rose from 219 on Wednesday to 410 on Thursday. They said that the deterioration was because the cloud cover trapped air pollutants and prevented them from disappearing. Besides the fine particle pollution that are measured by the Air Quality Index, the ozonegas levels were very high in the city at almost two times the safe.

Experts said that fine particle pollution or PM2.5 can penetrate inside an individual's lungs and cause damage to the health of people. The exposure to ozone gas can cause respiratory distress and can worsen lung diseases like chronic bronchitis and asthma. They said that this can result in permanent lung damage in individuals, inflaming their airways. The rise in the level of ozone gas is mainly due to extreme high temperatures in Delhi and the level is expected to remain high until rainfall starts in the capital. The weather experts also said that the UV levels were also very high in the area.

GufranBeig, project director of System of Air Quality Weather Forecasting and Research (SAFAR) said, “Ozone is created in conditions of high temperature and direct sunlight, accompanied with high levels of oxides of nitrogen (NOx), carbon monoxide (CO) and other volatile organic compounds (VOCs). They peaked this week probably because temperatures were extremely high.”