// Local time zone is Asia/Kolkata with offset GMT +0530

var dt = "14/03/2016";
var dtz = "14/03/2016 +0130";
var tz = "+0130";
var df = "DD/MM/YYYY";
var dfz = "DD/MM/YYYY Z";

var d1 = moment(dtz,dfz); // date string with time zone
var d2 = moment(dt,df); // date string without timezone
var d3 = moment(dtz,dfz).utcOffset(tz); // date string with time zone. Apply UTC offset after moment is created
var d4 = moment(dt,df).utcOffset(tz); // date string without time zone. Apply UTC offset after moment is created

d1.format()
// "2016-03-14T04:00:00+05:30"

d2.format()
// "2016-03-14T00:00:00+05:30"

d3.format()
// "2016-03-14T00:00:00+01:30"

d4.format()
// "2016-03-13T20:00:00+01:30"

d1.toDate()
// Mon Mar 14 2016 04:00:00 GMT+0530 (IST)

d2.toDate()
// Mon Mar 14 2016 00:00:00 GMT+0530 (IST)

d3.toDate()
// Mon Mar 14 2016 04:00:00 GMT+0530 (IST)

d4.toDate()
// Mon Mar 14 2016 00:00:00 GMT+0530 (IST)