After the eruption of the Hayli Gubbi, a shield volcano in Ethiopia's Afar region, thick clouds of volcanic ash and sulphur dioxide have travelled at speeds of 100-120km/h to reach India.
Though it is not expected to have a major impact on Air Quality Index (AQI) levels in Gujarat, Maharashtra, and Delhi (where it has already arrived) as it moves at a height of 15,000-45,000 feet, the ash clouds have affected a number of flights operating in the region.
The Directorate General of Civil Aviation (DGCA) has also advised that airlines avoid ash-affected airspaces, revise flight planning, and immediately report any suspected ash encounter, including engine issues or cabin smoke/odour.
How did these poisonous ash clouds reach India?
When a volcano erupts, it sends ash clouds into the sky with a lot of force. Hot air and gases help the ash clouds rise even further—to an altitude of about 5-15km, where it can move without being affected by changes in weather conditions, as it is above cloud level.
The strong east-west winds on this level of the atmosphere then pushed the ash clouds across the Red Sea, towards Yemen and Oman.
When even satellite images show the ash clouds as a large carpet of smoke moving quickly, one can imagine the real thing would definitely cover a vast area about the size of a town or more.
The ash clouds continued their journey in an east-northeast direction, crossing Pakistan to finally arrive at Gujarat's coast late on Monday.
It eventually loomed over Delhi-NCR, Haryana, Punjab, and Uttar Pradesh later into the night, as per independent forecaster IndiaMetSky Weather.
Where will it go?
With no plans to stop in India, the ash clouds would be moving towards China next (via the Himalayas), the India Meteorology Department (IMD) said.
"The latest analysis suggest that Ash plum has moved away from Northern India into China and it will transit into upper atmosphere and finer dust will liner in upper atmosphere for some days and move towards Pacific along with the Subtropical Jetstream," IndiaMetSky Weather added.
The forecaster has also pointed out a small trail of sulphur dioxide about 15km in the atmosphere, which will disperse over time.