When did the first riots between Hindus and Muslims happen in India?

According to the wikipedia page list of riots in India, the first riot involving Hindus and Muslims occured in the 1881. That riot is titled as "The Salem riots of 1882". This riot has its own wiki entry which says:

The Salem riots of 1882 is a term used to refer to serious Hindu-Muslim disturbances which took place in the city of Salem, Tamil Nadu in the then Madras Presidency in August 1882.

The cause of Salem riots according to wikipedia,

The riots are believed to have originated by the objection of Hindus to the construction of a mosque by the Muslims of the Sevvoypettai area of the city of Salem on the path of a Hindu religious procession.

[Note: I disagree a bit with the above quote. The riot was instigated by nationalist Hindus which should be specified. Labelling them as "Hindus" may offend the people of Hindu community.]

The wiki page further says:

Full-scale riots erupted in August 1882.[3] For three days, the British government had no authority in Salem city.[3] The mosque was pulled down and there was indiscriminate killing on both sides.1 Eventually, peace was restored. Large number of alleged suspects were arrested, speedily convicted and given harsh imprisonment terms at the Andaman Cellular Jail.

The aftermath of the riots according the wiki page,

The atmosphere continued to remain tense till 1884. The police arrested a large number of Indian nationalists accusing them of instigating the violence. The partisan behaviour of the Madras government and Governor's handling of the situation were sharply criticized by the Indian media. Indian nationalist newspaper The Hindu criticised the administration thus:

... the prosecution of the so called Salem Rioters and their convictions were the result of a premeditated design, hastily formed and executed in a vindictive spirit, not very honourable and utterly unworthy of a civilised Government....

In simple words, the Muslims wanted to build a mosque near a Hindu possession and Hindu nationalists objected. When the mosque was built or partially erected, some Hindu nationalists attacked and crushed it. This initiated the communal riots that affected the both communities. Before the riots, British divide and rule policy was responsible for making the two communities dislike each other.

I think first we should understand riot in its present context. Riot is an extreme form of lawlessness where administration is not able to control the violent mass which is indulged in criminal activity of many kinds targeted against particular group. Rulers or people associated with rulers massacring the helpless civilains should not be considered as riot. With this definition, though the first Hindu - Muslim Riot was Moplah Rebellion an Anti Hindu rebellion conducted by the Muslim Mappila community (Moplah is a British spelling) of Kerala in 1921. Moplahs murdered, pillaged, and forcibly converted thousands of Hindus. According to one view, the reasons for the Moplah rebellion was religious revivalism among the Muslim Mappilas, and hostility towards the landlord Hindu Nair, Nambudiri Jenmi community and the British administration that supported the latter. Adhering to view, British records call it a British-Muslim revolt. The initial focus was on the government, but when the limited presence of the government was eliminated, Moplahs turned their full attention on attacking Hindus. Mohommed Haji was proclaimed the Caliph of the Moplah Khilafat and flags of Islamic Caliphate were flown. Ernad and Walluvanad were declared Khilafat kingdoms. Annie Besant wrote about the riots: "They Moplahs murdered and plundered abundantly, and killed or drove away all Hindus who would not apostatise. Somewhere about a lakh (100,000) of people were driven from their homes with nothing but their clothes they had on, stripped of everything. Malabar has taught us what Islamic rule still means, and we do not want to see another specimen of the Khilafat Raj in India." The second and the most important was of the Direct Action Day of 16th August 1946 when the then Bengal premier Huseyn Shaheed Suhrawardy had announced a leave (for the administration!) and freedom for the rioters . . . Its a big topic.

A quick search of Google netted this entry from Wikipedia. The page says that conflict started in 711 CE with Islamic expansion, specifically by the Umayyad Caliphate. While this doesn't qualify as a riot, this marks the start of violent relationships between the two groups. This is reiterated here and here, although the time frames differ slightly from each other.

If you want to know exactly when the first riots were (defined as "a noisy, violent public disorder caused by a group or crowd of persons, as by a crowd protesting against another group, a government policy, etc., in the streets" from Dictionary.com), that information may be impossible to find. There was almost certainly resistance against Muslim rule by Hindu groups, but this waned and waxed with the Muslim ruler. Some rulers were very open to Hindu culture, such as Akbar, and probably warranted little unrest from Hindus because he allowed them to maintain normalcy in day-to-day living. Other were more aggressive toward Hinduism, inciting revolts. The ones cited there are the late 17th century.

The complexity is compounded when you look at Hindu tolerance for diversity. Many Hindus probably felt that as long as Muslim rule didn't negatively impact the way they lived their lives, it didn't matter. Riots would be uncommon in an environment where people were already content.

In addition, the issue is further muddled by the large number of differing groups within India and those taking control of India, of which there were many. During these time periods there was no unified Hindu or Muslim group, but there may have been hatred between smaller sects. Unified deviance from one large group toward another would have been impractical given modes of transportation and speed of communication.