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LIGO-India: A Decadal Assessment on Its Scope, Relevance, Progress, and Future

The LIGO-India project to build and operate an advanced LIGO (aLIGO) gravitational wave (GW) detector in India in collaboration with LIGO-USA was considered and initiated as an Indian national megascience project in 2011. Procedural formalities and site selection efforts progressed since then and the provisional approval for the Indian national project was obtained in 2016, immediately following the first direct detection of gravitational waves with the aLIGO detectors. With KAGRA GW detector in Japan being tuned to be part of the GW detector network, it is now the occasion to assess the progress of LIGO-India project, and evaluate its relevance and scope for gravitational wave science and astronomy. Various key factors like human-power, management, funding, schedule etc., in the implementation of the project are reassessed in the backdrop of the evolution of the global GW detector sensitivity. In what I consider as a realistic estimate, it will take more than a decade, beyond 2032, to commission the detector even with a fraction of the projected design sensitivity. I estimate that the budget for implementation will be more than doubled, to about Rs. 35 billion (> $430 million). The detrimental consequences for the project are discussed, from my personal point of view. However, a revamped action plan with urgency and the right leadership can make LIGO-India a late but significant success for multi-messenger astronomy for several years after 2032, because of its design similitude to the operational aLIGO detectors. For achieving this, it is imperative that the LIGO-India detector is replanned and launched in the post-O5 upgraded A# version, similar to the projected LIGO-USA detectors.