In my village (Ganges plain, North India), making achaar was a significant seasonal community event. When mangoes were small, we used to wait for heavy winds during early monsoon. A lot of raw mangoes would fall on the ground, and the next day they would be sold at a much cheaper price.
There were two broad classes of mango varieties: one for eating ripe, and the other one for making achaar, which were usually very small, had large seeds, and were extremely sour when raw (and extremely sweet and full of fibers when ripe). The whole process would take a week or two: cutting raw mangoes, drying them, salting them, preparing masala, and putting them in a special jar.
The last process requires special hands if you wanted your pickle to last a few years. There were a few women who were experts in putting pickle in jar and were highly sought after. Whoever had pickle that could last at least two years in the village without growing fungus belonged to this group. Some members of this famous group were from lower castes, and obviously, they were not allowed to physically touch the pickle. Instead, they would supervise from a very close distance.
They would take a few pieces of mango mixed with masala and push them down the jar as hard as possible to remove all air. The slower and harder you push, the better. Once the jar was almost filled, it would be filled with mustard oil and crystal salt and then kept for at least 6 months. The older the pickle, the better it is! The achaar jar used to be the costliest pot in a house, usually a china pot.
My contribution to this was introducing potassium permanganate as an extra layer to fight fungus. It is still known as "achaar powder" in the village. Things are very different now. The moisture content in new brick-concrete houses is not as high as it used to be in traditionally made houses. And much better quality jars are available, especially the airtight ones. I don't think many people now push the achaar as hard as they used to.