I am covering the major contribution which should be seen in the positive mode and categorized as follows. However missionaries work was not free on controversies because of conversion related issues which I am just skipping...
Democratization of education
Education in India was a privilege of elite upper classes. It was limited to gurukuls where upper caste young boys would go to study under the tutorship of a guru. Even women from the upper caste families were not provided the opportunity to learn. Common people were aliens to this elite education system. When missionaries arrived they began to start schools for common people, generally in the vernacular language.
The first book to be published in India was the Tamil Bible. Zigenbalg who came to Tranquebar in 1706 translated the Bible in Tamil language. Following his footsteps, William Carey translated Bible into several languages. Missionaries not only translated Bible, but also wrote grammar and produced dictionaries for several languages like Tamil, Bengali, etc…
Missionaries who saw the need for scientific health care began mission hospitals in India. Christian missions contributed much to the medical scene in India. Mission hospitals were started in several districts in the country. Modern medicine was made available to all people. Doctors treated patients with love, concern and care.
Famines ravaged much of India from 1870 – 1920; especially Deccan famine in 1877 and Central India famine in 1897. American missionaries responded in 1901 by supporting 16,000 orphans. Godfrey Philips said in 1936, "Of the six million Indian Christians, the great majority are of depressed class origin. Yet no one thinks of the Christian community as a depressed class. The church has actually uplifted more depressed class people than all other organizations put together." Feeding the hungry, taking care of children who were orphaned by famines, providing opportunity for the people by training them in some skills were the services rendered by missionaries during famines.
Mental patients were considered as demon possessed by the people in olden times. They were tied or chained, beaten, iron rods were heated and applied on their parts of body and controlled by a variety of methods. Medical missionaries pioneered ways to treat mental patients so that they have an opportunity to be rehabilitated in the society. Nur Manzil in Lucknow is one shining example of this contribution to India.
The tribals in Chottanagpur area in the modern Jharkhand state became Christian in large numbers. During the British Raj, many non-tribals tried to usurp the land of tribals. One Catholic Father Levins was always available to help these tribals to fight cases in the courts of law and get their land back. This unique service attracted many to Christianity.
Agriculture was the predominant occupation in India. The new methods of irrigation and crop rising was introduced by missionaries. Allahabad Agricultural Institute was a pioneer in this area which was also a contribution of missionaries.
With the advent of industrial revolution in the West, industries also began in India. Christian young men who had some education but did not have skills to be employed caused concern in the minds of missionaries. There were opportunities for young people to be trained and employed in such industries. But, there were not training centres for young boys. Missionaries started technical institutes like Nave Institute, Shahjahanpur, Prakash Institute, Wadi and Ingraham institute in Ghaziabad. These institutes trained young boys from all communities and they were able to build their career and families thorough this form of empowerment.
Rehabilitation center for criminals
Criminals who were thrown in jails had almost death sentence for life. It was not possible for them to again be rehabilitated in the society. Missionaries started rehabilitation centers for such people to help them to cope up with life. They were trained and provided micro-credits to start a small business and build their lives. Many who do not have such encouragement and opportunity would go back to the life of crime. Bethel, in Danishpet and Prison Fellowship of India, are some Christian organizations that provide help and support for prisoners families. The women were trained to manage the family. Children were provided with education and some times admitted in Christian hostels. When both parents are in jail the children are taken in hostels.