It is six hours behind the UTC and is based on the mean solar time of the 90th meridian west of the Greenwich Observatory.
ມັນແມ່ນຫົກຊົ່ວໂມງຫລັງ UTC ແລະແມ່ນອີງໃສ່ເວລາແສງຕາເວັນສະເລ່ຍຂອງທິດຕາເວັນຕົກ 90 meridian ທາງທິດຕາເວັນຕົກຂອງ Greenwich Observatory.