Water. I don’t even trust bottled water in India. I drink the filtered stuff any time I stay with family, because they all largely avoid water when out themselves, and resolved to filter my own this time. Christina pointed me towards bottles with self-contained filters, but the only one I found was a Pure Hydration one with a filter in the cap. Essentially, you pour any old water in, preferably without particles, shake it up and leave for 15 minutes. Then squeeze through the filter in the cap and drink. I believe that the shaking releases iodine into the water and then the filter takes that out and anything that might be dodgy still in the water. Works perfectly, but you don’t get a massive water flow if you’re really thirsty, like chugging from a bottle. But the bottle is made of this new microbe-resistant plastic and it doesn’t get dirty or skanky. The filter lasts for approximately 350 litres and fails-safely. The water becomes harder to squeeze through as the filter becomes exhausted, so you only ever get clean water, but you will end up getting nothing. Good call.