Polythene (nylon? some form of plastic, anyway) bags are the normal containers for milk in both Poland and India. Cartons tend to cost rather more in both places. However, we buy milk in waxed-paper bags (maybe foil backed, I'll have a look when I get home) for just a tad more than the polybag price (13 rupees as against 10 for a half litre, if you want to know), as we find the stuff in plastic bags often goes off within a day. Don't know if that's due to the packaging or inefficient pasteurisation though - the stuff we buy now is UHT, I think.