AllABCDEFGHIJKLMNOPQRSTUVWXYZ O Oases Definition: Fertile spots in deserts with water availability.Prelims Pointers: Artesian wells.PYQ: UPSC Prelims 2014Current Affairs:... Learn More → Objectives Resolution Resolution moved by Jawaharlal Nehru in December 1946 outlining principles of the Constitution.Source of Preamble... Learn More → Oceanic Crust Definition: Thin crust beneath oceans.• UPSC Pointers: Basaltic; thickness ~5–10 km. Learn More → October 16, 1905 Definition: Date of Partition of Bengal implementation.Prelims facts: Observed as a day of protest and... Learn More → Olivine Definition: A silicate mineral common in mantle rocks.Key Facts: Green in color; rich in Mg... Learn More → Open Market Operations Definition: The buying and selling of government securities by the RBI in the secondary market... Learn More → Opportunity Cost Definition: Opportunity Cost refers to the value of the next best alternative that is foregone... Learn More → Orbiting Carbon Observatories Definition: NASA satellites measuring atmospheric CO₂.UPSC Traps: Measures concentration, not emission sources directly.Current Affairs: Used... Learn More → Orogeny Definition: Mountain-building process through intense folding, faulting and compression.Prelims Pointers: Associated with convergent plate boundaries;... Learn More → Outcome Budget Definition: A budget document focusing on outcomes and results of government spending rather than just... Learn More → Oxbow Definition: Horseshoe-shaped lake formed from a cut-off meander.Prelims Pointers: Mature stage of river.PYQ: UPSC Prelims... Learn More → Ozone hole Definition: Seasonal ozone depletion over Antarctica.UPSC Traps: Not a literal hole.Current Affairs: Signs of recovery... Learn More → Ozone Layer Definition: Ozone-rich stratospheric layer.UPSC Traps: Different from ozone hole.Current Affairs: Linked to UV protection. Learn More →
