any suggestions for gas gyser

Sochna bhi Maat.
Kyu apni maut ko dawat de rahe ho.

Slow Poison , it releases Toxic  gas , and gets trapped in the small bathroom  and we inhale  that toxic gas

Highly injurious to health.

Also illegal , as gas company wont allow you permission, if you still do it and they come to know about it then they will take legal action on you

Ensure that gas geyser is installed outside bathroom. And there should be cross ventilation in your bathroom.

Go for instant electric geyser