Visas: Six month multiple-entry visas are now issued to most nationals regardless of whether you intend staying that long or re-entering the country. Only six-month tourist visas are extendable. Be careful to check whether your visa is valid from the date of entry or the date of issue.
Health risks: Cholera, dengue fever, dysentery, hepatitis, malaria, meningitis (trekking areas only) and typhoid. Many of India's larger cities are highly polluted and travellers with respiratory ailments may wish to take precautionary measures.
Electricity: 230-240V, 50 HZ
Weights & measures: Metric