How secure clean air in your residense or office? The answer to this question thanks researcher who resides essentially the most polluted cities in the planet: Delhi. The problem of lack of clean air and touched him personally due to allergies his lung ability decreased to 70%. With the help of NASA discovered how you can ensure access to oxygen while living even in such a polluted place like Delhi. The solution to your complaint is not found in another place than in nature. As it turns out, there are three regular houseplants, which are able to produce human survival even in a very tightly enclosed space!