Looks like Lantana camara - an aggressively invasive and very hardy species belonging to South & Central America, and now naturalized in many tropical areas of the world. It takes over quite rapidly in degraded forests and spreads through seeds.
We found it impossible to eradicate from our land in Uttarakhand - even after being manually dug up, it would regenerate through any little rootstock remaining. It completely covers the ground in dense thickets, allowing no native species room to grow. In its defence, though, the fruit is very popular with rhesus monkeys, langurs, and a wide variety of birds, especially bulbuls. It also provides cover to everything from tigers, cheetal, sambar, barking deer, and ground birds, such as thrushes, babblers, etc., where forest flora has been disturbed or removed.
By the way, there are some cultivated varieties as well - we have the yellow and the purple varieties in our garden in Gurgaon.
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