A war is low probability, high impact event, something we do not prepare ourselves for. However, it is not somethig which we can rule out. Last major war India fought was 40 years back in 1971. This does not mean that there will not be another one in next 40 years, especially since situation in Pakistan becoming highly unpredictable.
A major war means flight of capital from country, very high inflation and big devaluation of rupee. Conventional portfolios with allocations in equities and debt do not provide hedge against war.
Anyone living in big city is dependent on efficiency of supply chain management, basically on "just in time" deliveries for lots of day to day items. This will certainly get disrupted especially with petroleum products directed towards war front. Also, there will be power cuts due to shortage of fuel. Hence, life in big cities would be really tough during war. Best way to escape these troubles is to have agriculture land in rural area with ground water source where one can grow food and relax with relatively less problems.
War will also result in many fortunes made and lost. Almost all conventional portfolio will get hit. Hence, one needs to have something alternative to come out in better shape. Here also, it is much better to own physical Gold and foreign currencies which are considered safe heaven. Towrds the end of war, almost all conventional assets like stocks & property will be available very cheap and interest rates on FD would be quite high. One can use potful of Gold and FD in swiss franc (just for example) to buy these assets.
Few more things very useful to own are cigarettes and beer. See, these things will also face shortages and will have great demand. If you own cigarettes and beer, you can offer the same in exchange of services. It surely makes life easier.