﴿ فَكَذَّبُوهُ فَأَخَذَهُمْ عَذَابُ يَوْمِ ٱلظُّلَّةِ ۚ إِنَّهُۥ كَانَ عَذَابَ يَوْمٍ عَظِيمٍ ﴾

“But they gave him the lie. And thereupon suffering overtook them on a day dark with shadows: and, verily, it was the suffering of an awesome day!”

فَأَخَذَهُمْ عَذَابُ يَوْمِ الظُّلَّةِ so they were seized by the torment of the Day of Canopy. - 26:189 عَذَابُ يَوْمِ الظُّلَّةِ (the Torment of the Canopy), mentioned in this verse refers to an incident, which is this: Allah Ta’ ala sent down such an extreme heat on a people that they could not find comfort either inside the houses or outside. Then He sent down a mass of dark cloud over a nearby forest, under which there was a cool breeze. As the entire people were distressed due to excessive heat, they ran to take shelter under the cloud. When all of them assembled under the cover of the cloud, it rained fire instead of water. Thus the whole nation was burnt to ashes. (Ruh al-Ma’ ani)