India's wheat export ban, announced on 13 May, impacts up to 4% of global exports, on USDA forecasts for 2022-23 (March year end).
The combination of the heatwave, which will hurt crop yields, and another higher than expected inflation print, have likely driven this decision.
This is another significant instance of food protectionism, following Indonesia's ban on palm oil exports (c50% of global exports) and China's ban on phosphate fertilizer exports (c20% of global exports).
Export restrictions likely push global food prices even higher: which means more pain for poor, net food-importing countries. eg Bangladesh, Pakistan and Philippines in Asia, Jordan and Lebanon in Middle East, and Egypt and Nigeria in Africa.

India's wheat exports
India was aiming to increase its wheat exports over this period to 10-15mn tons (5-7% of global exports), according to comments from Food and Commerce minister Goyal in April 2022.

Most of India's historic wheat exports are to Bangladesh, according to India DGCIS data for 2021.

Out of the top 10 largest importers globally, Bangladesh is India's only significant customer – it sells to Indonesia and others but only in small volumes.
In mid-April, Egypt, which accounts for over 5% of global imports, approved India as a wheat supplier.
