Whenever any new technology emerges there is rightfully a concern about its impact on social life, health and environment. This was seen when first trains were run. People were worried if there would be effect of travelling in a train. In the 20th century many new technologies such as nuclear, semiconductors, communication, computer and Nanotechnology were developed. In the 21st century even a common man knows the benefits of new developments in science and technology. However, along with comforts achieved by adopting various technologies, mankind is now facing numerous problems. The problems are not limited to any small country or community, to rich or poor but to all. Major problems being faced are due to increased population in developing and underdeveloped countries, old and new diseases, depletion of natural resources like fossil fuel, oil and water, increased number of wars, terrorism and so on. Some of the problems are also related to global climatic changes, scarcity and quality of food and water as well as increased pollution in big cities. Therefore some often asked questions are: whether nanotechnology would help to solve or increase some of these problems? Do nanomaterials harm human bodies, animals or plants, may be by inhaling or by contact? Will nanomaterials pollute water, air and food?