The ash clouds from volcanic activity in Ethiopia that have drifted to India have had a negligible impact on Delhi’s air quality index, which remained very poor at 353 on Tuesday compared to 382 on Monday.

IMD director-general Mrutyunjay Mohapatra said the ash clouds were drifting towards China and they would move away from India by Tuesday evening.

The civil aviation ministry said there was no cause for concern and only a few flights were rerouted or told to fly at a lower altitude as a precaution.

A mixture of sulphur dioxide and ash content, the plume moving towards the northern part of the country had triggered concern over worsening air quality in the national capital, where the air index has been “very poor”.

Mohapatra said the ash clouds may have impacted flight operations because of the plumes moving in the upper-tropospheric region at heights of around 10-15km, but they did not have any effect at the ground-surface level.

He said the ash would not have any effect on air quality in Delhi and nearby regions.