What type of insect is this? Is it ant or something else?
Such a queer species. I thought it was an ant. But it is actually a spider. 

These spiders belong to Salticidae family,commonly called ant-mimicking spiders / jumping spiders.


  They are  Batesian mimics of ants, such as Sphecotypus in the Clubionidae.


They do not feed on their model organisms and keep them at an acceptable distance.

This one is from Myrmarachne sp. There are more than 20 species found in India.



Source: 


Wikipedia
Myrmarachne