Being Indian I've grown up with mangoes and have eaten them every summer since childhood. Mango is India's most popular fruit and it's hundreds of varieties all different regionwise, make it a pan-India fruit with few parallels, barring maybe bananas. Mangoes are rightly called the King of Fruits in India. And the King of King of Fruits is only one and that is the Alphonso Mango if you go by the popularity and craving for any one mango variety across India.
Maharashtrians, people from the state where the real Alphonsos grow do not consider other varieties to be mangoes. When I first heard this, I thought it was just regional pride, as each of India's regions has its own favourites both visually attractive and tasty. However as I've experienced over a decade, Alphonsos trump all other mangoes as anyone who has eaten that and other varieties will let you know and vouch for.
India is the native home of mango, meaning the fruit originated here. History and Indian literature have references to mangoes form thousands of years ago. The Alphonso Mango was popularised in India nearly five centuries ago by the Portuguese who named it after their commander Afonso de Albequerque who helped them conquer India. The variety propagated by grafting (not multiplied by seed) has since then been grown along the Western Indian coast primarily in the state of Maharashtra and also Goa. Today the best Alphonsos come from Ratnagiri and also from Devgadh both in Maharashtra though the variety is grown in orchards in Gujarat and Karnataka too.
Alphonsos start arriving in the market by February which is one reason for their popularity as other varieties only arrive later. Their arrival is eagerly awaited and ones getting their hands on first fruits of the season earn bragging rights (though they may even pay up to INR 200 per fruit). After March it is a frenzy for mangoes with Mumbai's street corners all flooded with Alphonsos real and lookalike, naturally or forcibly ripened and people shopping for them in hordes. Alphonsos were gifted to Queen Elizabeth in 1953 during her coronation which helped make the fruit get global acclaim. Being golden yellow outside and orange inside, they are a delicious fruit mostly sweet with just a touch of sourness. Alphonsos don't need refrigeration as they keep well in the open. At best, their skin wrinkles as they dehydrate. They have thin skin and thin stone delivering more pulp per fruit. The pulp is sweet, creamy and non fibrous. The fruit can be eaten as is or cooked into a range of dishes. A well ripened Alphonso is easily recognised by its sweet bewitching fragrance and attractive golden-yellow colour streaked with red. The fruit is harvested carefully with part of the stalk left on the fruit to aid ripening. Just use of straw is good to enable and hasten ripening. A ripening fruit helps fruit around it ripen too and such fruits emit a lot of heat.
Eating Alphonso mangoes for breakfast, lunch and dinner is a ritual at Mumbai homes of some communities with the fruit pulp a common form that is consumed. It is as though the Alphonso mango was created to offer relief from the oppressive heat and humidity of the city summers. Whatever it be, you've basically missed a delicious experience if you have not eaten a well ripened sweet Alphonso in season as the taste is indescribable. Being the most expensive mango and sold by number and individually harvested, handled, packed and eaten Alphonso is India's King of King of Fruits. It is also called Hapoos or Apoos in Marathi.
Where to buy Alphonsos if you live at Thane: The best source of course would be friends who hail from Konkan and ask them they bring back the mangoes from their visit to their native place where Alphonsos are grown. However, buying Alphonsos from seasonal shops set up in summer is also an option. At Thane the Gokhale Road area has several such shops which offer Alphonsos. If you buy unripe fruit buy it with straw in a box and ripen it within the box. Godrej Nature's Basket at Hiranandani Estate and Hiranandani Meadows also stocks Alphonsos which are naturally ripened and thus likely to be sweet and tasty. Those not minding a drive can head out to Dadar or Matunga which have many shops selling Alphonsos. Alternately one can drive to MAFCO market or APMC wholesale fruit market both at Vashi where Alphonsos are sold. One can buy in bulk at the APMC Market and get unripe mangoes wrapped in straw inside wooden crates.
Spotting fake or artificially ripened mangoes: This is not easy but not impossible either. Naturally ripened fruit emit a sweet aroma that will be missing in chemically ripened fruit that may only look ripe. Over ripe Alphonsos start wrinkling but are still good to eat. They continue to smell good even when over ripe.