For setting curd, a small amount of curd is added to warm milk. The microbes present in the curd help in setting if the temperature of the mixture remains approximately between 35°C to 40°C. At places, where room temperature remains much below the range, the setting of curd becomes difficult. Suggest a way to set curd in such a situation.
In order to keep the temperature from 35°C to 40°C, curd can be surrounded by the insulator such as jute, woolen material etc so that heat cannot escape outside and, in this way, temperature does not drop below 35°C.
Also, One can place the curd directly in sunlight in order to maintain the temperature in the range of 35°C to 40°C.