The MileagePlus site http://www.united.com/page/article/0,6722,1151,00.html indicates that upgrades of Full-fare United Economy (Y and B class) tickets from both North and South Asia to North America should cost 15,000 miles ONE-WAY, which is normally 30,000 miles for round trip travel. My experience is that when a government ticket is in Y class, that is what it costs to upgrade.