Most fruits and vegetables can be preserved longer in a low-temperature environment (around 4~8°C), but mangoes need to be stored at high temperatures.
If a mango is placed at room temperature or in a low-temperature environment (especially a low one) after being picked, it will start to develop black spots and spoil within about a day or two. A day or two is not enough for transportation, so mangoes are generally transported with a layer of quicklime at the bottom of the box. This serves three purposes: to absorb moisture, to generate heat, and the high temperature is also beneficial for ripening unripe mangoes. Therefore, the mangoes you see on the supermarket shelves are all warm—because they have just been taken from a warm box.
Also, never put mangoes in the refrigerator for storage.