It's quite a low wage, but not 5 rupees an hour: 8000 / 160 = 50. 50 rupees an hour is probably a decent wage in a small town / city in India, but would be a tough wage to live on in Bangalore.
Apple assembles (some) phones in India in part to reduce tax/tarrif costs more than to reduce labor costs. Not all of the produced phones will be sold in India, but a lot of them will, and I think the exported ones will still count toward quotas for reduced tarrifs.