Turbidity

noun (uncountable)

/tɜːˈbɪd.ɪ.ti/

The cloudiness or haziness of a fluid (primarily water) caused by suspended particles such as silt, clay, algae, organic matter, or microorganisms. Turbidity is measured in Nephelometric Turbidity Units (NTU); India's drinking water standard under BIS (IS 10500:2012) sets a permissible limit of 1 NTU (desirable) and 5 NTU (maximum permissible). High turbidity in rivers and lakes reduces light penetration, inhibiting photosynthesis, clogging fish gills, and smothering benthic organisms — making it a key water quality parameter monitored under India's National Water Quality Monitoring Programme.

✍️ Usage in a UPSC answer

Post-monsoon turbidity spikes in the Yamuna at Palla, Delhi's main intake point, regularly exceed 3,000 NTU, straining water treatment infrastructure and supplying impetus for upstream catchment management investments.

Synonyms

cloudinessmurkinessmuddinessopacityhaziness

Antonyms

claritytransparencypellucidityclearness

🌱 Word Family

turbid (adjective), turbidly (adverb), turbidimeter (noun), turbidimetry (noun), turbulence (related noun)

🔡 Root

Latin turbidus = muddy, disturbed, from turba = crowd, commotion; -ity = state or quality

📜 Etymology

From Latin turbiditas (muddiness, confusion), derived from turbidus (muddy, thick), which comes from turba (a crowd, uproar, disturbance). The Latin root turba is also the source of turbulent and disturb. The word entered English scientific usage in the 17th century, initially in optics and chemistry.

🧠 Memory Hook

TURBID = TURBA (crowd/commotion in Latin). Turbid water is crowded with particles — a commotion of silt and algae that makes it murky. Think of a disturbed crowd — turbidity is water that has been 'disturbed' and is now murky.

📝 Seen in UPSC Question Papers

Prelims 2012 — Public Health

Real UPSC previous-year questions whose text uses “Turbidity” — proof this word earns its place on your list.

🌿 Environment & Ecology 📖 Seen in: Ecology Fundamentals — Ecosystems, Foo...

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