What is the right age for an Indian child to wear contact lens?

Wearing — and caring for — contact lenses is a serious responsibility and it takes some maturity to handle it well. Your child will need to remember to clean his contacts each time he wears them and wash his hands before he inserts them, or he could wind up with an eye infection or worse. And he may have to make important decisions about his lenses (such as when to take them out) without your help when he's away from home.

Many children are mature enough to handle the duties of wearing contacts at age 10. Consider what you know about your child: Does he remember to wash his hands before dinner and do other chores without being told? If so, he's probably mature enough to wear contacts. The bottom line is that your child must be motivated (the drive to wear them should come from him, not you) and responsible. Also keep in mind that a child of this age should wear contact lenses only as needed — while playing sports or for a special event, for example — rather than wearing them every day.
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Comment: As per my wife, an ophthalmologist with significant pediatric experience, it would be useful to delay contact lens use till the child is at least 13 years old and is responsible enough to take care of the contact lens by themselves.