I need to make a pilgrimage to Varanasi in India. What city is the nearest airport located.?

I need to make a pilgrimage to Varanasi to perform worship at the Kashi Vishvanath temple. I only have limited leave from work and would like to stay in India for as quickly as possible. After a ritual bath in the Ganges, I would pray at Kashi Vishvanath, Annapurna Devi, and Kaal Bhairava then promptly leave the city. What is the nearest city with an international airport where I could fly from Sydney, Australia? Would I use the train to get to Kashi? Thanks.