Lets consider the scenario, if one node in India, finds the nonce (in pow) and it will generate the block and propagate to the network. How the block will move across the each and every node of the network?. is it by gossip or ghost protocol?. If that is the case, in 10s - 12s whether it will reach to the entire node in the world and they will work for next block?. What about the poor internet connectivity countries like Africa?.
The new block will move around basically by gossip. The Ghost protocol has nothing to do with propagation it (or actually its variant Why did Ethereum abandon the GHOST protocol?) is used to make the network more secure with uncle blocks. Here's some info about Ghost: https://www.cryptocompare.com/coins/guides/what-is-the-ghost-protocol-for-ethereum/
Network latency is exactly the issue why a method is required to determine the correct chain. In Ethereum the heaviest (similar to longest) chain is considered the correct chain so clients switch mining to the heaviest chain.
If you have a poor connection you will probably create more uncles than others. So you will not get as big mining rewards on average.