Locally this tree is known as Nahar but looking up online I came up with several other names. The Poached Egg tree seems to be most appropriate going by the appearance of the white four-petalled blooms with a yellow centre. But it’s also known as Ceylon ironwood (it’s the national tree of Sri Lanka), and Cobra’s Saffron. The botanical name is Mesua ferrea. The plant is named after the heaviness of its timber, and cultivated in tropical climate for its form, foliage, and fragrant flowers.
The tree has many medicinal properties. According to Wiki, the fresh as well as the dried flowers of the Nahar are used as a remedy for dysentery, itching, nausea and other ailments. But the main extract from the tree is the oil that is produced from the flowers. More on the medicinal uses of the plant can be found here.