Cleaning and conservation of river Yamuna in Delhi
A K Jain
About 90 per cent of Yamuna river water is diverted into drains and canals upstream and most of the remaining water is stored for urban use, leaving the river high and dry, especially during the summer. River without a continuous flow lacks oxidation and becomes stagnant and polluted...[more]

GNSS Constellation Specific Monthly Analysis Summary: April 2025
Narayan Dhital
The article is a continuation of monthly performance analysis of the GNSS constellation. Please refer to previous issues for past analysis. As an addition, there is a section that explores mathematical concepts of variational equations used in the estimation of satellite clocks and orbits. This is in turn linked to the challenges of estimating orbits of inclined geosynchronous and geo-stationary satellites in QZSS and Beidou constellations... [more]

Emerging underwater survey technologies: A review and future outlook
Osayi Philip Igbinenikaro, Oladipo Olugbenga Adekoya and Emmanuel Augustine Etukudoh
Recent advancements in underwater survey technologies have significantly improved our ability to explore and understand the depths of our oceans, lakes, and rivers . This review aims to analyze the latest advancements in underwater survey equipment, including their operational benefits and potential areas for future development.... [more]