5-1? Did you mean 5-0?
Aus have 3 matches when India finishes their series against Eng. Aus needs to win all 3 to ensure their top position.
NZ also have 3 (2 against weak/new SA lineup), if they win all 3, they can also claim No.1 spot.
There are too many permutations & combinations. But safe to say, if India manages 4 wins (and don't lose any points on slow over-rate), they'll be no.1 irrespective of other results.
As smith moved to opening
India should also nove vk to top
As india still not find propper opening partner of rohit sharma and match will be turning track so before ball get's old vk can utilise more