Why Sudden rise of grey hair in mumbai specially 18-25 age

In last 2-3 years i have seen a very high rise of people with premature grey hair in mumbai outliers mira Bhayandar, vasai-virar. What could be the biggest reason junk food, over usage of phone,laptop or stress maybe even covid vaccine💀. (Also if anyone stopped thier grey hair or even reversed it what did you do?)