Why my battery health is 97% in just 1month?

Hello nidhi199,

Thanks for using the Apple Support Communities. We understand that you have concerns regarding the health of your iPhone battery. The health being at 97% is considered a healthy battery and there is no need to be concerned.

Your battery will age due to several factors:

iPhone usage

Battery charge cycles

Age of battery

If you review, iPhone Battery and Performance, under section: Your battery's maximum capacity, the following is noted.

"A normal battery is designed to retain up to 80% of its original capacity at 500 complete charge cycles when operating under normal conditions. The one-year warranty includes service coverage for a defective battery. If it is out of warranty, Apple offers battery service for a charge."

If you would like to look over tips to help preserve the life of your iPhone battery, look at, Maximizing Battery Life and Lifespan. Here you'll find some really good tips to help you get the most out of your battery.

Best regards.