Uttarakhand glacier disaster and cascading catastrophe on hydel projects resulting in loss of human lives and properties is a wake-up call on safety concerns over mega hydel projects under construction and pushed in fragile and earthquake-prone Arunachal Pradesh. It has also focused attention on the concerns expressed by environmental activists over the sustainability of the development strategy of looking at perennial rivers of the Himalayan region only as powerhouse. Union Minister of State for Power and New & Renewable Energy R.K. Singh has gone on record stating that Sunday's disaster has caused an estimated Rs 1500 crore to the National Thermal Power Corporation's 520 megawatts Tapovan-Vishnugad hydel project. The glacial burst led to the rising of water levels in the river Rishiganga, which washed away the Rishiganga small hydro project of 13.2 MW. About 197 people are reported missing, 35 of them stuck up in the tunnel of the power project while bodies of 20 people have been recovered. The under-construction Tapovan-Vishnugad hydel project is a run-of-the-river project and was targeted to be commissioned in 2022-23. Around 13 villages have been cut-off after a bridge collapsed and swept away in the disaster site which speak volume of the resultant effects of the disaster. Arunachal Pradesh government's stated position in the State Assembly is that "hydropower can be a great revenue generator" and the State government is streamlining its development. Many power developers are showing interest in hydropower in Aruanchal Pradesh and the government would look for genuine developers. In a prebudget consultative meeting Arunchal Pradesh Chief Minister Pema Khandu stressed the need for development of power project in the state and asserted that for the state to sustain financially hydropower is the key. He informed that major hydropower projects in the state are being expedited. The 600-megawatt Kameng hydel project has been commissioned while work of 2880-MW Dibang and 1750-MW Lower Demwe projects to start soon. The 2000-MW Lower Subansiri project is also targeted to be completed by 2022. There have been strong protests over the safety and adverse impact of these mega power projects in downstream areas in Assam and also in Arunachal Pradesh. Experts have also been flagging concerns over the safety aspects as well as adverse impact on fragile ecology and livelihoods in downstream areas. The scientific opinions are, however, divided with some experts backing these mega power projects in Aruanchal Pradesh stating that required technology is available to ensure safety and also mitigate adverse impact in downstream areas. Lessons must be learnt from Uttarakhand disaster and more consultations with experts should be held to address the concern of the people in downstream areas before pushing the mega projects in Arunachal Pradesh. Advantage of smaller hydro power projects that cause less damage to the fragile ecology must be weighed against the risk of natural disaster causing wanton damage to a mega dam project and cumulative impact in downstream areas. India pushing for mega projects in upper reaches of the Brahmaputra in Arunachal Pradesh is guided by the principle of establishing first user's right to counter China building mega hydel projects on the international river known as river Yarlung Zangbo in its Tibet Autonomous Region to establish its first user's right. Dam proponents push the run-of-the-river projects as sustainable projects with minimized impact on ecology as it has either small storage capacity or no storage as compared to a traditional storage-based hydel electricity project. But the run-of-river projects blocks migrations of fish and other aquatic species which are crucial for sustainable livelihoods for people living along the river, more particularly in downstream areas. Regulated flow of river water has adverse impact on wetlands which are replenished by seasonal floods in the river, critical to conservation of the wetlands that are sources of livelihood of scores of people. The impacts in downstream of the glacier burst will lead to amplify the apprehension of similar catastrophe in Arunachal Pradesh and Assam. This is likely to lead to intensification of anti-mega dam movement in Assam. It is time to examine the question the development model adopted for ecologically fragile northeast and Himalayan region. The mega projects result in massive destruction of pristine forests including rain forests which can never be compensated by undertaking plantation drives. The 2880-megawatt Dibang multipurpose project cleared by the Central government involves felling of 3.24 lakh trees on forest land. A cumulative impact assessment of the safety of the dams and downstream impact of the dams under construction as well as the proposed mega dams in Arunachal Pradesh and other areas of the Himalayan region should precede their execution.No development model can be sustainable in which people and environment are not central. It is hoped that the Uttarakhand disaster will be an eye opener for the central and the state governments concerned and all other stakeholders.