What is the scientific name of this tree?
It is Lagerstroemia, perhaps Lagerstroemia indica, the common crape myrtle. 

https://en.wikipedia.org/wiki/Lagerstroemia

Myrtle in french means blueberry: "From Medieval Latin myrtillus, diminutive of Latin myrtus (“myrtle”), from Semitic: Arabic مُرّ‎ (murr, “bitter”), Hebrew מֹר‎ (mor, “bitterness") ." Myrtle is an unrelated family with tough spicy seed pods which are used as a condiment including eucalyptus. 

Crape, refers to the frilly flowers, from Latin Crispus, Crispy: frilly, crèpe is often used to refer to frilly fabric and it also means pancake in french, which is a chapatti with butter and milk and an egg from the bible.

Because you said it is common, I checked google images for "india frilled pink flower tree", it was about 20 images in. There should be a Hindi/Indian script of the wiki page, with the Indian derived name.