8th September 2025

Explanation – A Blood Moon occurs during a total lunar eclipse when the Earth is positioned directly between the Sun and the Moon. The red-orange appearance is due to Rayleigh scattering, where shorter-wavelength blue light is scattered away, and longer-wavelength red light passes through Earth's atmosphere. During totality, the Moon is within the umbra, the darkest part of Earth's shadow, causing it to appear red-orange. However, the visibility of a Blood Moon depends on geographic location and local atmospheric conditions—it is not always visible globally, as evidenced by events like the 2022 Blood Moon which was not visible in India due to occurring during daytime. 

Explanation – CoWIN is a user-friendly mobile app for recording vaccine data and works as a beneficiary management platform with various modules including administrator, registration, vaccination, beneficiary acknowledgement and reports. The app is not restricted to primary beneficiaries only; it was designed to serve all eligible beneficiaries for COVID-19 vaccination, not just healthcare workers. The platform uploads bulk data on co-morbidity provided by local authorities and maintains a database of healthcare workers. 

Explanation – The Strait of Malacca connects the Andaman Sea (Indian Ocean) and the South China Sea (Pacific Ocean), not the Bay of Bengal and East China Sea. It runs between the Indonesian island of Sumatra to the west and peninsular Malaysia and extreme southern Thailand to the east. Singapore, Malaysia, and Indonesia jointly patrol the Malacca Strait. Roughly 60% of India's seaborne trade and almost all of its LNG imports pass through the Malacca Strait, making it strategically crucial for India. 

Explanation – The HKH region stretches 3,500 kilometres and spans eight countries: Afghanistan, Bangladesh, Bhutan, China, India, Myanmar, Nepal and Pakistan. It is considered the Third Pole (after the North and South Poles) and contains the largest volume of ice and snow outside of the Arctic and Antarctica. The HKH region is the source of ten large Asian river systems: the Amu Darya, Indus, Ganges, Brahmaputra, Irrawaddy, Salween, Mekong, Yangtse, Yellow River, and Tarim. The basins of these rivers provide water to 1.9 billion people, a fourth of the world's population. 

Explanation – The Indian Science Congress is organised by the Indian Science Congress Association (ISCA), which is an independent body functioning with the support of the Department of Science and Technology, not in direct association with it. The first session of the Indian Science Congress was indeed held in 1914 at the premises of the Asiatic Society, Calcutta. The Science Congress is an annual five-day event that brings together the scientific communities on a platform for interaction with students and the general public.