Yes, I think India needs to have more than one standard time because India has a large longitudinal extend of about 30°:
(a) When the sun is still shining in western coast it is already night in northeast so we need two or more time zones to clearly reflect day to day changes.
(b) Time variations is of 2 hours between Easternmost and the Westernmost parts of our country. The sun rises two hours earlier in Arunachal Pradesh as compared to Gujarat because the earth is tilted and also it rotates in East to West direction so during rotation the Eastern part of the world experiences that sun rays earlier as compared to the western parts of the world.
(c) In other countries like USA, Canada and Russia have more than one standard time because their longitudinal extend is large. India’s longitudinal extend is also 30°. Therefore, it is advisable to use more than one standard time.