Why 0 use before any mobile number?

Answer 1

0 deffferentiates Local calls from STD and ISD calls in the previous years when land lines are extensively in use.... so the rules continued to mobile world too as it is the extension olden years...so we are using a 10 digit dialling form like "0xxxyyyyyyy" out which xxx - indicates area telephone exchange code and rest yyyyyyy - gives the land line number.

if you are making alocal call no need to dail any area code as the call in intended within the same exchange area. so your call'll not go out of the current exchange .

if you try for STD or ISD you should dial area code like XXX folloed by number YYYYYYY preceded these two by a "0" this to indicate the exchange you are trying to go out of the exchange area so the exchange'll try to check the free link to connect to the dialled exchange is free or not if it is free it give rng and ring back tones for both caller and called parties.

so now also even after mobiles arrived India is divided into circle of telecom & each circle is considerd as an Exchange in olden days and links are formed from circle to circle . so differentiate circle we are using "0" hether too... tht's all