Removing water is the oldest form of preservation and still the most reliable one that needs no cold chain. Take a mango from roughly 83% water down to under 15% and there is not enough moisture left for mould or bacteria to work with. Everything else follows from that single change.
The arithmetic is what makes it a business rather than a hobby. Eight kilograms of fresh mango becomes about one kilogram dried, so a July glut bought at seasonal prices becomes stock that sells in December at a price the fresh fruit never reaches. That dried kilogram occupies an eighth of the space, needs no refrigeration, and survives a courier van in Multan in June.
Temperature is the part people get wrong. Fruit dried at 55–60 °C keeps its colour and most of its vitamin content; pushed to 75 °C to save four hours it case-hardens — a dry shell over a wet centre that spoils in the bag two weeks later. A thermostat that actually holds its setting is the difference between product and waste, which is the whole reason a cabinet beats a rooftop.