The competition to supply Air Independent Propulsion-equipped submarines to the Indian Navy has intensified as Spanish company Navantia installs a Hydrogen-based AIP into an S-80 class submarine for Project-75I. This move challenges German shipbuilder Thyssenkrupp, which claimed the only proven AIP system. The Navantia AIP, named BEST, generates hydrogen on demand, offering tactical advantages and safety enhancements. This technology, combined with Lithium-ion batteries, allows submarines longer underwater missions. Navantia's system, despite being selected by the Spanish Navy, faces competition from Thyssenkrupp's fuel cell-based AIP. The Indian Navy urgently needs AIP submarines to modernize its fleet and counter China's naval presence. AIP technology is crucial for enhanced undersea warfare capabilities in different regions. The adoption of AIP technology can bolster the Indian Navy's strategic position against adversaries and potentially outmatch Pakistan's submarine capabilities.