Once in use, insulin has to be stored at a temperature of 15-25 degrees Celsius. In many countries, this would equate to room temperature, but in India, in typical hot summer, this is much lower than the room temperature.
Hence, though not strictly recommended, in India, it is ideal for storing the insulin in the refrigerator (in the compartment where water bottles are kept) to maintain a temperature of 15 - 25 degrees Celsius. Unopened insulin vials or cartridges must always be stored in the refrigerator. Remember, it must NOT be frozen.