CM3.1-8 | Environmental Health — Glossary

Secondary sewage treatment in which sewage is aerated in a tank with return sludge containing active microorganisms that metabolise organic matter, followed by sedimentation of the resultant biological floc.

Dengue, chikungunya, and Zika vector; day-biting; breeds in clean stored water in domestic containers; larva hangs head-down via siphon; rests parallel to surface.

CPCB's 0-500 scale translating pollutant concentrations into six colour-coded health categories; used for real-time public communication about air quality.

Infection by Entamoeba histolytica causing invasive colitis (flask-shaped ulcers, bloody diarrhoea) and extraintestinal disease (amoebic liver abscess); transmitted via contaminated water or food.

Total confirmed malaria cases per 1,000 population per year; the primary indicator for malaria elimination progress; India's target is API <1 per 1,000 (elimination).

The malaria vector genus; rests at 45° to surface; larva lies parallel to water surface; breeds in clean slow-moving/stagnant water; night-biting.

Chronic arsenic poisoning from contaminated water or food, characterised by palmoplantar keratoses, skin hyperpigmentation/depigmentation, and increased risk of bladder, lung, and skin cancers.

The proportion of disease cases in a population attributable to a specific risk factor (e.g. PM2.5); used in health impact assessment to quantify pollution-related disease burden.

A soil bacterium producing crystal proteins selectively toxic to mosquito and blackfly larvae when ingested; non-toxic to fish, mammals, and non-target insects; used as a biological larvicide.

Progressive increase in the concentration of a persistent pollutant (e.g. DDT, mercury) through successive levels of a food chain.

Waste generated during diagnosis, treatment, or immunisation of human beings or animals; regulated under BMW Management Rules 2016 with mandatory colour-coded segregation and treatment.

Indian Standard Drinking Water Specification setting acceptable and permissible limits for physical, chemical, and bacteriological parameters of drinking water.

The mass of dissolved oxygen consumed by biological processes in a water/sewage sample over 5 days at 20°C; the standard measure of organic pollution; CPCB requires treated effluent BOD ≤30 mg/L for river discharge.

The technique of adding chlorine to water until all oxidisable material is consumed and a stable measurable residual is achieved, ensuring effective disinfection.

Number of Aedes-positive containers per 100 houses inspected; BI ≥5 indicates significant dengue transmission risk.

Haemoglobin bound to carbon monoxide (with 240× affinity vs oxygen), which cannot carry oxygen; the key biomarker and toxicological species in CO poisoning.

An AB5 exotoxin produced by Vibrio cholerae that ADP-ribosylates the Gs alpha subunit of adenylyl cyclase, causing persistent cAMP elevation and massive intestinal fluid secretion.

Water treatment step in which a coagulant (typically alum) forms a gelatinous floc that traps fine particles, colloids, and bacteria, enabling their removal by sedimentation.

Lymphatic filariasis (Wuchereria bancrofti) and Japanese encephalitis vector; breeds in polluted/organic water (drains, cesspools); night-biting; larva hangs via siphon.

Mottled enamel hypoplasia caused by fluoride ingestion >1.5 mg/L during tooth development; a marker of chronic fluoride excess.

Radiation effect occurring above a threshold dose, with severity increasing with dose (e.g. acute radiation syndrome at >1 Gy, cataract at >0.5 Gy).

Helminthic waterborne disease caused by Dracunculus medinensis acquired via drinking water with infected Cyclops copepods; on the verge of global eradication.

Introduction of contaminants into the natural environment at concentrations that cause adverse effects on living organisms and their ecosystems.

Control of all environmental factors with deleterious effects on physical, mental, or social wellbeing; encompasses excreta disposal, solid waste management, sewage treatment, and housing standards.

An RNA virus transmitted by the faecal-oral route (contaminated water); causes self-limiting hepatitis in the general population but fulminant hepatic failure with ~30% case-fatality in pregnant women in the third trimester.

Combustion products (PM2.5, CO, PAH) generated by burning solid biomass (wood, dung, crop residue) for cooking or heating indoors; affects ~500 million Indians and is targeted by PM Ujjwala Yojana.

Application of a residual insecticide to interior walls, ceilings, and furniture to kill endophilic (indoor-resting) vectors that contact the surface after blood-feeding.

WHO-recommended strategy combining biological, environmental, chemical, and personal protection measures for sustainable vector control, with emphasis on minimising insecticide use and resistance.

Electromagnetic or particulate radiation with sufficient energy to eject electrons from atoms, producing ions; causes deterministic (threshold) and stochastic (no-threshold) biological effects.

Government of India programme (2019) targeting piped water supply to every rural household by 2024, with GP-level water quality testing laboratories and community monitoring.

A bed net factory-treated with pyrethroid insecticide that maintains insecticidal activity for 3-5 years without re-treatment; distributed free in high-malaria areas under NVBDCP.

An arthropod that carries a pathogen externally (on body or mouthparts) without the pathogen developing or multiplying within the vector; e.g. housefly transmitting Salmonella.

Oxidation of haem iron from Fe2+ to Fe3+, producing methaemoglobin, which cannot bind oxygen; caused in infants by high nitrate water (blue baby syndrome).

A bacteriological water quality test that estimates the most probable number of coliform organisms per 100 mL using multiple dilutions in lactose broth tubes.

National Ambient Air Quality Standards—India's regulatory concentration limits for eight pollutants notified by MoEFCC under the Air Act 1981, revised 2009.

India's 2019 national programme targeting a 20-30% reduction in PM2.5 and PM10 concentrations by 2024 in 122 non-attainment cities.

National Centre for Vector Borne Diseases Control — India's national programme for malaria, dengue, chikungunya, lymphatic filariasis, kala-azar, and Japanese encephalitis prevention and control.

Permanent, irreversible destruction of cochlear outer hair cells caused by sustained exposure to sound levels ≥85 dB(A) for ≥8 hours/day.

SBM Phase II standard requiring ODF status plus functional solid waste management (collection, segregation, processing) and liquid waste/greywater management at village level.

A community status certifying that no member defecates in the open; verified by community survey and observation; achieved nationally under SBM Phase I (October 2019).

Chemical class (e.g. malathion, temephos) that irreversibly inhibits acetylcholinesterase, causing cholinergic crisis; antidote is atropine + pralidoxime (given within 24-48 hours).

A sleeping density of <500 cubic feet of air space per adult in a room, or >2 persons per sleeping room; promotes airborne disease transmission including tuberculosis.

India's affordable housing programme targeting pucca houses with built-in toilets for below-poverty-line families under both Gramin (rural) and Urban streams.

Inhalable particulate matter with aerodynamic diameter ≤10 µm; deposited in the upper airways and bronchi.

Fine particulate matter with aerodynamic diameter ≤2.5 µm; penetrates to alveoli, crosses into the bloodstream, and causes cardiovascular and systemic effects beyond the lung.

Physical removal of solids from sewage by screening and sedimentation; removes ~30-35% of BOD; does not kill pathogens.

Synthetic analogue of natural pyrethrum (e.g. permethrin, deltamethrin) that prolongs voltage-gated Na⁺ channel opening; the preferred class for ITNs and IRS due to low mammalian toxicity.

Collection and storage of rainfall—from rooftops or surface run-off—for direct use or groundwater recharge; rooftop systems use first-flush diverters and sealed storage tanks.

The concentration of free chlorine remaining in treated water at the consumer's tap after disinfection; BIS requires ≥0.2 mg/L as evidence of effective treatment.

A toilet that isolates excreta from human contact, prevents fly/vector access, avoids groundwater contamination, and has no odour nuisance; includes pour-flush, VIP, and twin-pit designs.

The biologically active layer at the surface of a slow sand filter, consisting of bacteria, algae, and protozoa, which degrades organic matter and removes pathogens by predation and metabolic activity with 99.99% efficiency.

Biological oxidation of organic matter in sewage by activated sludge process or trickling filter; removes 80-90% of BOD; some pathogen reduction.

Radiation effect that is probabilistic with no threshold dose; probability increases with dose but severity does not (e.g. radiation-induced cancer, heritable mutations).

India's national sanitation programme targeting elimination of open defecation (Phase I: ODF by 2019) and solid/liquid waste management at village level (Phase II: ODF Plus by 2025).

An arthropod in which the pathogen undergoes development or multiplication as part of its life cycle, and which transmits the pathogen to a vertebrate host during feeding.

Illness caused by ingestion of water contaminated with pathogenic microorganisms or toxic chemicals; transmission is via the faecal-oral route for biological agents.

Water that is safe from pathogens, free from harmful chemicals, palatable (colourless, odourless, pleasant taste), cool, and free from suspended impurities.