I have been travelling to Sikkim for the last 16 years and it's become harder to get cash out of the ATM's because of high fraud skimming cards that just rely on card strips and not the more secure chip and pin system.
Skimming card in India is a multi million pound industry and the banks have taken control and made it harder to get money out this way. The banks have computerised security barring systems that automatically bar credit cards abroad that pose a high risk which means that you need to know what to do in this eventuality.
My recommendation, first tip, is to bring some cash with you but it's hard to get rupees in the UK before you fly out. The Post Office and other outlets in the UK don't provide rupees (INR) because its a closed currency so get it at your destination airport. The exchange currency shops in the airport have chip and pin so it always works and authorises first time. You need cash on you, as in our world, has become more of a cashless society but India are a few years behind.
My second tip, Once you have cash then you need to know that Indian ATM's are not as prevalent as in the UK and that queues appear at busy times and you could wait up to 20 minutes to get at the ATM. ATM's in India are always enclosed in a room and sometimes they have a security guard making sure that skimming is not taking place. The security guard is not always in uniform and they will help you to make your transaction and normally speak good English.
My third tip, Many ATM's are clunky and some just do not work which can become a frustration. You can take 40,000 INR (around £500) from ATM's in India per day at a maximum of 10,000 INR per transaction. You don't need to inform your bank that you are going abroad as everything is now computerised.
My fourth tip, Bring a number of credit cards with you for example, Mastercard and Visa seems to work well but American Express doesn't seem to work. I use my AmEx card for internet transactions for accommodation in India.
My fifth tip. Make sure you are on your own in the room if there are no security guard present and shield the number pad from view when you key in your PIN
My sixth tip, Try at least another ATM if you are refused cash as the communication links for the bank's server can be poor.
My seventh tip, Before you leave for your holiday, setup VOIP on your mobile. VOIP is a way to connect with UK landline numbers without paying high call charges. I paid £114 for a single call to the UK to release the bar from my card only to find out that another bar had been placed straight afterwards. It costed me another £83 for a second call to release the higher security bar from the same card. Try setting up Viber Out or Skype on your smartphone as calls can be as little as 1p per minute. You need to be connected to the internet and most hotels have free internet available. I use a coffee shop at MG Marg in Gangtok which provides great western coffee and free internet.
My eighth tip, Sometimes you just need to make calls on your phone and my £197 phone call charges were next day reimbursed after making a complaint and also getting a £30 inconvenience payment. Most banks are willing to foot these charges to reduce fraud in India. You have to go through a lot of security questions and know what recent transactions have been made on your account. I spent time with the advisor on the phone whilst I made the transaction on the ATM in real time.
My ninth tip, There are two levels of security bars which are set up by the credit card providers. You have to provide answers to more security questions at level 2 but once that has been lifted, there are no more restrictions place on your card. If you can, make sure you stay on the phone whilst you try to take money out on level 1, if you are immediately barred again, then your advisor can put you through to another person who is on level 2
My tenth and final tip, Read through everything I have mentioned and setup the VOIP because forewarned is forearmed. There's nothing worse than trying to sort things out on the fly as stress levels can rise and it can spoil your holiday