Natural Ways to Lower Humidity at Home:
Humidity plays a big role for human comfort situation. Basically we need to understand that the comfort level is combination of temperature and humidity (DBT & Rh). In tropical weather the third most important factor is air flow velocity. As the air become stagnant the humidity levels go up. A comfortable level of relative humidity range for human being is 25-60% with different temperatures.
There are some basic steps for having humidity at lower or comfort range in homes. Like,
a) Heavy / frequent use of flowing hot water for bathing or similar purpose when bathrooms are adjacent and directly opens in the home / room causes humidity increase in the home. To avoid the same try to have better ventilation / exhaust in bathrooms so that humid air from bathroom does not ex-filtrate to home / room.
b) Make necessary arrangements for the room or home to have adequate windows for fresh air circulation at the highest rate. This is the most effective way. High humid areas like kitchen, bathrooms, wash areas etc. Must be mechanically ventilated or should have enough opening area (window) for additional humid air to get escaped from the room. A closed volume / room have high tendency for humidity increase.
c) Indoor plants tend to release considerable amount of humidity to the room. Indoor plants should be kept near to the ventilation opening / window. Also one should avoid over watering these plants.
d) A certain level of humidity can be controlled by heating up the room as higher temperature air can carry more humidity (water grains). But this definitely does not provide enough comfort in hot tropical weather of India.
Above are common ways to have relief; however the efficiency of these things strongly depends on local weather conditions. For further needs, mechanical ways like AC, dehumidifier etc. will solve the purpose.