Answer
(Fatwa: 1343/1343=M/1430)
Melvisharam is your native place, you will perform full salah whenever you will go there. Chennai is your watan-e-iqamah (place where you stay), if you intend to stay there for 15 or more days, you will perform full salah and in case of having intention to stay for less than 15 days you will shorten the salah as qasr.
If you have settled in Chennai as your permanent residence, submit the question again.
Allah (Subhana Wa Ta’ala) knows Best
Darul Ifta,
Darul Uloom Deoband