Diwali is a celebration of human evolution,environmental awareness,enlightenment and consciousness.Diwali is celebrated in the month of October or November every year at the onset of winter. It is celebrated by Hindus, Sikhs, Jains,Sikhs and other communities all over the world. It has become a truly international festival which is being celebrated in more than hundred countries.

Deepawali means path of light.Deep means lamps. Aali means path.On a philosophicalnote, it can be said as path of enlightenment. Deepawali is also called Diwali, Deepotsava,Deep Parva,Prakash Parv,festival of light and Laxmi Puja etc.It is a five days festival.  

It starts from Dhanteras, which is considered the first day.Second day is Narak Chaturdashi or Chhoti Diwali. The third day is Diwali. 

The fourth day is Govardhan puja or Godhan Puja. It culminates on the Bhai Duj festival, which is celebrated on fifth day. 

There are many stories behind the celebration of this popular festival of Diwali. 

Bhagwan Ram came back to Ayadha after defeating the demon king Rawan.

The popular cultural belief sees it as festival of happiness and prosperity.Bhagwan Ganesh, the god of wisdom and auspicious start, is worshipped along with Devi Laxmi, who is goddess of wealth and prosperity.

The first scientific secret lies in this worship and belief only.

In Indian culture knowledge has been given more importance than pure material wealth.

This worship of knowledge along with wealth creates a society which prosper and thrive on rationality, research, teaching and scientific lifestyle. Ayurveda, Yoga, Khagolsatra(astronomy),natural farming, daily bathing,food habits, protection of environment,temple architecture, metallurgy, rationality and six schools of philosophy etc are excellent products of this knowledge worship.These are gift of Sanatana dharma to the world.

India is a nation of rice growers. The harvesting of rice normally starts around the Navratri festival,which is celebrated before Diwali. 

The processing of paddy and arrival of dehusked rice takes about two weeks.

The first batch of freshly harvested rice arives in homes for consumption around Diwali. 

The psychotherapy through celebration based on acknowledgment of the arrival of harvested rice revitalize the whole agrarian society. 

The pomp,the fire crackers, diyas (oil lamps),new clothes, sweets, exchange of gifts, worship in homes and decoration of dwellings give the largest booster dose to the whole economic system of Indian subcontinent. 

Some may see it an agrarian festival as farmers are the real beneficiaries of rice harvest.

In reality, ut touches everyone. It benefits weavers, potters,gardeners, flower sellers, oil extractors, construction workers, painters, carpenters,ironsmith,rice millers,sweet sellers,jewelers, traders,candle makers,fruit growers, basket makers,milk producers, farm workers etc.

This redistribution and quick circulation. of wealth ensures that everyone is happy and content. 

This festival ensures that this happiness is expressed openly through community celebration. 

After this psychotherapy comes the scientific aspect of health, hygiene and sanitation. 

By the end of monsoon the many wild and unwanted plants engulf every open space around our homes in Indian subcontinent.Growth of fungus, virus and bacteria is at the peak during the monsoon season.

With the festival of Diwali arrives the need of cleaning every part of our homes and their surroundings.

Normally, whitewashing with lime is done during Diwali. 

Lime ,being a disinfectant, kills most of the bacteria,viruses and fungus in our homes.

Bright sunlight and removals of weeds make this cleaning really effective. 

Next scientific aspect is elimination of the unwanted insect population. During the monsoon, the insect population also increaes manifolds.Weeds,moisture, less sunlight and abundance of food help in population explosion of these insects.

By removing the weeds and unwanted plants, we largely eliminate the host plants for insects. However, insects survive in areas which are somewhat far from the home. 

When we light oil lamps during Diwali, all insects from the nearby areas come en mass and die near these lamps being lighted all around the house.That is why these oil lamps are placed outside the house.The area around the house is also lightened with oil lamps.Very few lamps are kept inside the house. 

The lamps kept inside are also placed near doors and windows only. 

The strategic placement of oil lamps ensures that all insects outside and inside the house are killed .

We must thank ancient rishis and scholars of India, who invented this unique low cost scientific method to eliminate unwanted insects and weeds. 

A grand success is achieved without spending a single penny on costly, poisonous and carcinogenic modern pesticides. 

There are many more scientific aspects of Diwali which are not mentioned here because of constraints of space. In nutshell, it can be said that Diwali is a very scientific, well thought and well appreciated festival which ensures redistribution of wealth, boosting of economic growth, psychological welbing and cleaning of environment for general wellness. 

It brings positive energy into human society and environment. 

It illuminates everyone. 

It eliminates darkness and spreads happiness.