crowds at public and street rallies. On 11 October, a rally was scheduled at Aliya Madrasha field. Thousands of people had gathered in the city; estimates were that it was the biggest rally in the city since the Awami League had assumed office in January 2009. Four-Party Alliance supporters gathered from several districts. Protest against Tipaimukh Dam The BNP was concerned about India's construction of the Tipaimukh Dam on the Barak River, which enters northeastern Bangladesh at Amalshid in Zakigonj. They believe it will have adverse effects in the region and contribute to desertification. The dam was planned decades ago, but resistance has developed against the project. In late 2011, Ali organized a day-long hartal (strike) and protests in the Sylhet district on 1 December to protest the Indian project. His programme also included mass rallies over several days, with participation by the BNP student group, Jatiyatabadi Chhatra Dal (JCD), as well as a rally and procession by Jatiyatabadi Shechhasebak Dal, and other front organizations. He urged all political parties to protest the Indian project. He said that, if the dam were not stopped, the protest movement would continue. The strike and protests proceeded without violent incident. Ali announced the BNP would stage other events, such as a human chain, hunger strike and grand rally at Amalshid, where the Barak River enters Bangladesh. Disappearance On 17 April 2012, Ali disappeared after last being seen in Dhaka at midnight with his driver. His private car was found by police near his Dhaka home, but the two men remain missing since. No groups took credit for his disappearance, nor was a ransom asked for. BNP announced plans for a hartal (general strike) in Sylhet in protest. The police said that BNP supporters had barricaded roads of the district and they were being called in. BNP members have also clashed with police in protests in Dhaka since his disappearance, where more than 30 people have been injured. By 22 April, conflicts had taken place especially in Sylhet and Dhaka; demonstrations and protests had also occurred elsewhere. BNP supporters led day-long hartals (strikes) for three consecutive days on 23, 24 and 25 April in the week following Ali's disappearance. Based on a petition from Ali's wife, ten government security agencies had to respond to the High Court's demands to produce Ali within 10 days; two had responded within the deadline, saying they did not