The flight was scheduled to depart at 0545 IST but was delayed 20 minutes due to one no-show passenger. The aircraft departed Bombay at 0605, and at 0620 the crew contacted Ahmedabad Approach Control. The METAR of 0540 IST was then transmitted to the crew, and again at 0625 the weather of 0610, due to visibility reducing from 6 km to 3 km. Clearance to descend to FL 150 was given at 0632 IST and the crew was advised to report when the aircraft was at 1700 feet overhead the Ahmedabad VHF omnidirectional range (VOR). Visibility was 2000 m in haze and the QNH was 1010. The QNH was correctly read back by the crew.