Regarding the original quiestion: getting wifi in T2 arrivals is impossible, the airport free wifi only works with a indian number, they are unable to send the verification sms to foreign phones at all. I arrived last saturday night and was unable to help a gentleman who didn't have a BA intin to show the CISF guard to enter the upper departure level and wanted to start the BA app with the wifi. The workaround was to ask someone for their mobile number, get the confirmation code on that phone and copy it to the wifi portal. too much hassle.