Surely, India's top level government will survive.
In india, the administrative structure is totally worthless and thats the reason why most of the India works in a very ad-hoc and corrupt fashion. While in west, we go for formal judiciary, economy, employment, education, infrastructure, healthcare etc, in India, everything is adhoc. Their majority prefers intervention of elders and kangaroo courts than judiciary. Their majority can only afford quacks than real doctors. Their majority believes in mob policing than proper formal cops -- heck they have very few cops per 1000 people. Their economy is mostly informal and based on cash. Education is also highly privatized in the hands of private schools and government schools are disfunctional. Electricity is unreliable. They still use fuels like wood/cow-dung a LOT.
At worst, they will loose their transport infra and will have to resort to ancient ones -- like they did in their lockdown period.
Over a period of 1 year or so they will be able to get most of the rudimentry administration back.
India is a living chaos. Its pretty hard to kill a living chaos like India. Its pathetic but it survives anything you throw at it.
None of these things cause instant or even near term death. At worst it makes your life shorter. Instead of typical 60 years of life expectency, people in India will have to make do with 40 years for sometime. Actually, I am not sure even it will go down. Radiation looks a hell lot scary than it really is.
Secondly most of India is still very informal and adhoc in its living and infra. They do not depend upon modern and more centralized infra as much as say americans do. A week of failure of electric system will make USA cities buckle, while in India it will be another summer.
I honestly cannot decide if you are just stupid or massively ill-informed.
The unofficial or the rudimentary part of economy exists because the organised official structures exist, they would not be able to operate without those top tier structures, if you do not know, then please do some more reading.
Those top tiers of social, economic and administrative structures allow the rest of the country to operate, they are the country, without them even a small fever used to kill people, so many things that are no longer life threatening because those top tiers have helped create a better situation. The only difference is that those top tiers are more visible in developed countries, but less visible in developing countries like India, but without those top tiers, there would be nothing left. That's a fact.
Without those top and middle tiers of any nation, there would be no health care system, the people will die, not just from the effects of nuclear blast but hunger and thirst and the radiation poisoning in the eco system. Because those issues will need to be tackled, they won't go away on their own. A rural peasant cannot do that especially when there is no food, especially when they have someone dying from radiation poisoning to look after. Even if they have access to food, that food could be killing them slowly from radiation poisoning.
The other illnesses that have been eradicated will come back, they would start killing in the millions, the radiation aftereffects would have such an impact on agriculture and water supplies that you would have no food for years, perhaps longer, but even months is enough.
How long can you live without food? The world won't be coming to feed you, that'll have their own problems.
You haven't got a clue, so please stop acting like an annoying child, and go learn something before you get run over by a bus, a person this stupid shouldn't be on the streets.
Or, perhaps you'll are living in Canada so who gives a crap about what happens in India, right?