For Surat, today (16 March 2026):

• Sunrise: about 6:47 am
• Navkārsi time: sunrise + 48 minutes ≈ 7:35 am IST

So, you should eat Navkārsi after about 7:35 am.

General rule for any day and any city:

1. Find that day’s local sunrise time.
2. Add 48 minutes.
3. That is your Navkārsi samay for that day.