What is windfall gain tax?
A windfall gain tax is imposed by the government on a company. When a corporate gains from something that it can't control or are responsible for, that financial gain is windfall profits.
After the reduction in the central excise duty and more expenses on fertilizer and food, the government's expenditure got increased. As a result, the government imposed a windfall tax on oil companies to compensate for the gap.
In simpler words, a windfall gain tax is a higher tax rate on gains that result from a sudden windfall gain to a particular organization or industry, usually as an aftermath of geo-political disturbance, natural disaster or war that creates uncommon spikes in demand or supply interruptions. Ukraine and Russia conflict is a prime example.