Why some countries have more than one time zones?
Many Countries have more than one time zones for different part of its territory. This id done purely on Economic interest. The Time gap between Western and Eastern most point of India is approximately close to 2 hours. But to avoid confusion India follows a single time zone. In North East States sun rises and sets early and in western part it raises and sets late ( in real sun doesn’t raise early or late, it is because of difference in longitude).
There is also a argument which states that because of this difference the North Est states are least developed compared to west as they waste precious man hours compared to west due to time lag. Some countries have adopted according to the location and hence they have different time zone.
It is actually better to have different time zones than one time zone.