my dog is facing problem while walking

Question
My dog used to love going out and walk long distances. But now she refuses to walk at all. I am not able to know the reason. We go in the morning at 6 with her for a walk due to the hot weather in India. In addition to that she has started to pant a lot.
Will be very glad to have your help at the earliest.

Answer
There is not enough information for me to comment on this except to say this.
If she isn't on heartworm prevention she needs to be tested for this and treated.
She could be having a heart problem which will make her unwilling to walk.
She could be having back or joint problems.

She needs to be seen by a vet to determine what is going on with her.
Make an appointment for your vet to look her over.