A factory in India this early into Tesla's manufacturing capability, which is still very low, makes sense when you think about world demand for M3. They will sell every car they make regardless of where the factory is located. Why split ANY unnecessary profit with the Chinese when you can keep every dime you make? 3-4 years down the road when China is needed for MY makes better sense, keep them waiting until things become more favorable on your terms.
Like many things in India this makes sense until you actually try to implement it. India is having a very hard time implementing solar at reasonable scale even though it is way more ideal for the country than coal.