@Joe Shearer why Telangana was formed? Why AIMIM opposed its formation?
You will have to bear with me. I can't give you a short reply.
Telengana - the erstwhile Hyderabad State - was being raped by the Telugus from the rich coastal districts. The local people, Hindu and Muslim, deeply resented the flagrant and cynical parcelling out of precious and premium-rated real estate in the heart of the city to 'carpet-baggers' from those other regions.
A brief word of explanation: Andhra Pradesh was constituted of three regions; the extremely rich and prosperous coastal districts, the rice-bowl of India, replete with very rich rice-merchants and rice-mill owners, and, in subsequent years, in granite mining as well; the grim, gang-infested land of Rayalaseema, whose lordlings everybody feared, as they were lords to themselves;
The light green stretch of coastland is Coastal Andhra, Vishal Andhra
The purple bit is Rayalaseema.
The scarlet bit is Telangana.
and the cultured, but somewhat 'laid back' Telangas themselves, those from Hyderabad being somewhat obsessed with matters cultural, those from the districts happy with their lot, farming a parched and arid land that gave them nothing like the fountains of cash that the coastal rice barons got.
In this set-up, after the iconic N. T. Rama Rao took to politics when a decent, undistinguished but respectable Telugu leader was insulted in public by Rajiv Gandhi, and won a crushing series of electoral victories, triggered by simmering Telugu outrage against this behaviour by Delhi, first there was a great deal of unity among the regions. Then Rama Rao's son-in-law, Chandrababu Naidu, decided that his father-in-law was not the strong and efficient leader that this large and significant state demanded, and swept him aside, captured his Telugu Desam Party and took power. He was the first Chief Minister to proclaim that Chief Ministers needed to be professional in their approach, and should think of themselves as the CEO of the state. He brought in teleconferences, and in his video-conferences with District Magistrate, he set a tough and challenging pace of governance for the entire hierarchy. It would appear that either he did not share the loaves and fishes of office among his own party, or among the other parties as well, because he was himself displaced by a revived Congress Party, led by a man named Rajasekhar Reddy. This man was a Christian from a corner of the coastal district, and allied by marriage to an extremely powerful family of iron-mining magnates around the Karnataka town of Bellary, just across the border from Andhra Pradesh; they, too, were Reddys, and not only had a finger in Andhra Pradesh politics, but were king-makers in Karnataka as well.
It was during Rajasekhar Reddy's tenure that the carpet-baggers swept in with full strength. Naidu had minted money nationalising and then selling off large tracts of land to developers and speculators, but he at least led the IT revolution in the state; by the time he finished, IT and offshore services revenues were in the ratio of 4:2:1 between Bengaluru, Chennai and Hyderabad. Hyderabad had arrived.
The carpet-bagger had also arrived. Under Reddy, more land was sold to these monied outsiders; where Naidu is thought to have earned hundreds of crores, Reddy is thought to have earned thousands of crores. Even though the people of Telangana were left seething with rage at these goings on, they lacked the electoral weight to drive out the bad elements and to annul the laws and regulations supporting them. It came to the point where they could finally take it no longer, and starting with the students at Osmania University, they started an agitation for a separated Telengana - in effect, ironically, a revived Hyderabad state. It was not surprising that there were frequent references to their last ruler, Mir Osman Ali Shah, and some resentment of the shabby treatment meted out to him after his surrender to Indian forces and to Sardar Patel.
At this critical juncture, as the Telengana agitation reached greater and greater levels, Chief Minister Reddy forced his pilots to take off in the government helicopter, in stormy weather, and perished in a helicopter crash in deep jungle in the far south, near his ancestral town. It was difficult from that point onwards to stop the increasingly insistent agitation for separation, and when the Congress leader, Sonia Gandhi, backed it, the national parliament decided (over the objections of the rice barons and the gangster lords) to separate out the province.
Nandamuri Taraka Rama Rao Chandrababu Naidu Y. S. Rajasekhar Reddy
In one sentence, it was resentment of outsiders, even though those were Telugu speakers too, who came and exploited the rather less than ambitious and hard-driving Telengana people.
A quick word about caste politics: the main struggle in united Andhra Pradesh was between Khamma NTR and his folks and the Reddys; the split was led by a Vellamma, land-owners who thought of themselves as the Rajas to the Reddy Choudharys, although they were a very small number (the Reddys do call themselves Choudharys, while the Vellamma call themselves what the British insisted on being known as, Dorays, Lords).
I am surprised by your suggestion that the AIMIM opposed the formation of Telangana. You probably know the background; the Razakar leader, Qasim Rizvi, on being released from prison in 1957, handed over the fragments of the party to a lawyer, Abdul Wahid Owaisi, who in turn groomed his son, Sultan Salahuddin Owaisi (Sultan was nothing but a part of his name, he held no royal office), whose eldest son, Asaduddin Owaisi, is today the head of that party. They were Congress allies until quite recently, and broke away at a time when they had been reduced to a single seat in the legislature, and thereafter joined hands with the separatist movement, the TRS, led by the present Chief Minister, K Chandrasekhar Rao, he of the wondrous proboscis. I don't have a clue about their objecting to the formation of Telangana.