In 1947, during the process of the withdrawal of the British from the Asian region, several Pashtu Muslim tribes took advantage of the transition process to mobilize against the authority of the Hindu Maharaja, Hari Singh, who controlled the region. Pakistan, interested in controlling the area, sent several of its soldiers (disguised as locals) to fight this first rebellion.
In a short time they managed to conquer the city of Muzzafarabad and, shortly thereafter, they left for Serinagar, capital of the state of Jammu and Kashmir. Pressured by the strength of the uprising, the then head of state sought support from India to contain this conflict. Taking advantage of Singh's unfavorable situation, Indian Prime Minister Jawaharlal Nehru managed to sign an agreement where India would have free military and economic access to Kashmir.
The Pakistani government, after denouncing the coercive stance of the Indian government, made official its participation in the conflict by sending regular troops. India, which had carried out a series of offensives against rebel forces, managed to regain part of the territories lost by the Kashmir government.
After a balance of forces, neither side achieved significant military achievements. Fearing greater attrition, Indian minister Nehru decided to mention the conflict during the 1948 United Nations Security Council.
Standing against Pakistani intervention, the UN Security Council demanded the formulation of measures to end the war. Among the main points of the resolution, Pakistan and India should unite in favor of holding a referendum that would decide the political future of Jammu and Kashmir.
After conflicts that killed around 1500 soldiers and rebels, a ceasefire monitored by the United Nations was decreed in January 1949.
20th century - wars - Brazil School
Source: Brazil School - https://brasilescola.uol.com.br/guerras/i-guerra-caxemira.htm