Soil and Noise Pollution
Soil pollution from agrochemicals, mining and fly ash, bioremediation and phytoremediation, and noise pollution: decibels, Noise Rules 2000 limits and loudspeaker rules.
Prerequisites
- Water Pollution, for biomagnification and heavy metals, which also move through soil.
- Soil Erosion and Conservation, for soil as a resource.
- Light and Sound, for loudness, amplitude and the decibel scale.
The Hook: The Field and the DJ
A farmer in the Chhattisgarh plains notices that each year he needs more urea for the same paddy yield, and that earthworms have become scarce in his field. Near Korba, a village grumbles that fly ash blows onto its fields. And in town, a wedding procession’s DJ booms past midnight while students next door try to sleep before their exam.
Soil and noise pollution are less visible than smoke or dirty rivers, but both are regulated, both damage health, and both are asked about. What are their causes, and what do the rules say?
Why it matters: Prelims asks about pesticides and their bans, bioremediation and phytoremediation, decibel facts and the Noise Pollution (Regulation and Control) Rules, 2000. Mains asks about the sustainability of chemical-intensive agriculture and about regulating noise.
Part A: Soil Pollution (मृदा प्रदूषण)
Soil pollution is the presence of toxic chemicals or unwanted materials in soil at levels that harm soil organisms, crops, animals or people, or that degrade soil fertility.
Causes
| Cause | How it pollutes | Example |
|---|---|---|
| Excess and unbalanced fertilisers | Over-use of urea and phosphates; soil acidification; nutrient imbalance; nitrate leaching to groundwater | Heavy urea use in irrigated paddy and wheat belts |
| Pesticides (insecticides, herbicides, fungicides) | Persistent residues kill soil organisms and enter food chains | Organochlorines such as DDT and endosulfan |
| Industrial waste and effluents | Heavy metals (lead, cadmium, chromium, mercury) | Tannery and metal industry areas |
| Mining | Overburden dumps, acid mine drainage, metal-rich runoff into fields | Coal and iron-ore mining areas |
| Fly ash | Dumped or wind-blown ash from thermal power plants | Around coal power stations |
| Urban solid waste | Leachate from unscientific dumps; plastics | Open dumping grounds |
| E-waste | Lead, cadmium and mercury from informal dismantling and burning | Informal recycling clusters |
| Faulty irrigation | Waterlogging and salinisation (salts rise and accumulate at the surface) | Canal command areas with poor drainage |
Effects
- Loss of soil micro-organisms and earthworms, so lower fertility.
- Toxic residues in crops, milk and meat, which then biomagnify up the food chain.
- Contaminated groundwater (nitrates, pesticides, metals).
- Barren or saline land unfit for cultivation.
Pesticides: what to know
| Pesticide | Status in India |
|---|---|
| DDT | Banned for agricultural use; restricted use continues for mosquito (vector) control under the public health programme |
| Endosulfan | The Supreme Court imposed a nationwide ban on its production, sale and use in 2011, following severe health effects in Kasaragod (Kerala), where it had been sprayed aerially on cashew plantations. It was listed under the Stockholm Convention on POPs in 2011 |
DDT and endosulfan are persistent organic pollutants (POPs): they do not break down easily, travel long distances and biomagnify.
Remedies: cleaning polluted soil
| Method | Meaning | Example |
|---|---|---|
| Bioremediation | Using micro-organisms (bacteria, fungi) to break down pollutants | Oilzapper, a bacterial consortium developed by TERI with Indian Oil, used to clean oily sludge and oil spills |
| Phytoremediation | Using plants to absorb, stabilise or break down pollutants | Indian mustard (Brassica juncea) takes up heavy metals such as lead; sunflower has been used for radioactive and metal contamination |
| Mycoremediation | Using fungi | Breaking down hydrocarbons and some pesticides |
| Physical/chemical | Soil washing, excavation, capping, liming of acid soils | Contaminated industrial sites |
Prevention is cheaper than clean-up:
- Soil Health Card Scheme (launched February 2015 at Suratgarh, Rajasthan): tests soil and recommends nutrient doses, so farmers use balanced fertiliser.
- Integrated Pest Management (IPM) and biopesticides (neem-based, Trichoderma, Bacillus thuringiensis).
- Organic and natural farming: Paramparagat Krishi Vikas Yojana (2015); vermicompost and biofertilisers (Rhizobium, Azotobacter, blue-green algae).
- Neem-coated urea (made universal in 2015) slows nitrogen release and curbs diversion of urea.
- Mining districts: red iron-ore fines from the Bailadila mines have been reported to wash into the fields and streams of villages near Kirandul (Dantewada); coal mining and overburden dumps affect land around Korba and Raigarh.
- Fly ash from Korba’s power plants is a soil and air problem; using it in bricks, cement, roads and mine filling is the remedy.
- Agriculture: chemical-intensive paddy in the plains raises fertiliser and pesticide loads, while organic and natural farming are promoted in the tribal north and south, where agrochemical use is traditionally low.
See Agricultural Science for biofertilisers and IPM.
Part B: Noise Pollution (ध्वनि प्रदूषण)
Noise is unwanted sound. Noise pollution is noise at levels or times that disturb rest, harm health or interfere with work and communication.
Measuring noise
- Loudness is measured in decibels (dB), a logarithmic scale: a rise of 10 dB is about a 10-fold increase in sound intensity, and a rise of 20 dB is about 100-fold.
- Standards use dB(A), a weighting that matches the sensitivity of the human ear, averaged over time (Leq).
| Sound | Approximate level |
|---|---|
| Threshold of hearing | 0 dB |
| Whisper | about 30 dB |
| Normal conversation | about 60 dB |
| Heavy traffic | about 80–90 dB |
| Loud DJ, firecrackers close by | 100 dB and above |
| Threshold of pain | about 120–130 dB |
These are typical figures; actual levels vary with distance.
Sources
Road traffic and pressure horns, aircraft, trains, industry and generators, construction, loudspeakers and DJs, and firecrackers.
Effects
| On | Effect |
|---|---|
| Hearing | Temporary hearing loss; noise-induced permanent hearing loss with prolonged exposure (occupational limits are commonly set around 85–90 dB for an 8-hour day) |
| Heart and mind | Raised blood pressure, stress, irritability, sleep disturbance, reduced concentration |
| Children and students | Poorer learning and memory |
| Wildlife | Disturbs communication, breeding and migration of birds and animals |
Noise Pollution (Regulation and Control) Rules, 2000
Made under the Environment (Protection) Act, 1986. The ambient standards, in dB(A) Leq:
| Area / zone | Day (6 a.m.–10 p.m.) | Night (10 p.m.–6 a.m.) |
|---|---|---|
| Industrial | 75 | 70 |
| Commercial | 65 | 55 |
| Residential | 55 | 45 |
| Silence zone | 50 | 40 |
Other key provisions:
- Silence zone: an area of not less than 100 metres around hospitals, educational institutions and courts, declared by the competent authority.
- Loudspeakers and public address systems cannot be used at night (10 p.m.–6 a.m.), except in closed premises such as auditoriums, conference rooms, community halls and banquet halls.
- The State Government may allow loudspeakers between 10 p.m. and 12 midnight on cultural or religious festive occasions for a limited period, not exceeding 15 days in a calendar year.
- Enforcement is by the authority the state designates (typically the District Magistrate, Commissioner of Police or another designated officer).
Judicial view: In In re: Noise Pollution (2005), the Supreme Court held that freedom from noise is part of the right to life under Article 21, and upheld the night-time restrictions on loudspeakers and on bursting firecrackers (10 p.m.–6 a.m.). Freedom of speech or religion does not include a right to use loudspeakers that disturb others.
Control measures: sound barriers and green belts along highways, silencers and enclosures for generators, bans on pressure horns, zoning (keeping industry away from homes and schools), green crackers (CSIR-NEERI), and enforcement of loudspeaker and DJ timings during festivals and weddings.
Memory Tricks
Don’t Confuse
| This | vs | That |
|---|---|---|
| Bioremediation — microbes clean pollutants | vs | Phytoremediation — plants clean pollutants |
| Silence zone — 50 day / 40 night | vs | Residential — 55 day / 45 night |
| Industrial night limit — 70 (only 5 lower than day) | vs | Other zones — 10 lower at night |
| Waterlogging and salinisation — over-irrigation | vs | Soil erosion — loss of topsoil by wind and water |
| Endosulfan — banned by the Supreme Court (2011) | vs | DDT — banned for agriculture, still used for vector control |
Common Mistakes
- “Doubling the decibel value doubles the loudness.” False. The scale is logarithmic; +10 dB is about ten times the intensity.
- “The silence zone limit is 40 dB(A) by day.” False. It is 50 by day, 40 by night.
- “Night time under the Noise Rules is 9 p.m. to 6 a.m.” False. It is 10 p.m. to 6 a.m.
- “DDT is completely banned in India.” False. It is banned for agricultural use but allowed for vector control.
- “Phytoremediation uses bacteria.” False. It uses plants; bacteria are bioremediation.
- “Noise rules come under the Air Act.” Careful. The Noise Rules, 2000 are framed under the Environment (Protection) Act, 1986. (The Air Act’s definition of air pollutant was widened in 1987 to include noise, which is why this confuses people.)
Practice
All questions below are original practice questions written in CGPSC style. They are not previous-year questions.
Level 1: Foundation
- The use of plants to remove heavy metals from contaminated soil is called ______.
- A silence zone extends at least ______ metres around hospitals, educational institutions and courts.
- Under the Noise Rules, 2000, the ambient limit for a residential area at night is ______ dB(A).
Answers
- Phytoremediation.
- 100 metres.
- 45 dB(A).
Level 2: Prelims MCQs
Q1. Consider the following statements regarding the Noise Pollution (Regulation and Control) Rules, 2000:
- The rules are framed under the Environment (Protection) Act, 1986.
- “Night time” under the rules means 10 p.m. to 6 a.m.
- The State Government may permit loudspeakers until midnight on festive occasions for any number of days in a year.
Which of the statements given above is/are correct?
- (a) 1 only
- (b) 1 and 2 only
- (c) 2 and 3 only
- (d) 1, 2 and 3
Answer and explanation
Q2. Match List I (Zone) with List II (Day-time ambient noise limit, dB(A) Leq):
| List I | List II |
|---|---|
| A. Industrial | 1. 50 |
| B. Commercial | 2. 55 |
| C. Residential | 3. 65 |
| D. Silence zone | 4. 75 |
- (a) A-4, B-3, C-1, D-2
- (b) A-3, B-4, C-2, D-1
- (c) A-4, B-3, C-2, D-1
- (d) A-4, B-2, C-3, D-1
Answer and explanation
Q3. “Oilzapper”, developed in India, is an example of:
- (a) phytoremediation using aquatic plants
- (b) bioremediation using a consortium of bacteria
- (c) chemical dispersant for oil spills
- (d) an incineration technology for oily sludge
Answer and explanation
Q4. Which of the following is the most likely result of prolonged over-irrigation without proper drainage in a canal command area?
- (a) Laterisation
- (b) Podzolisation
- (c) Waterlogging and salinisation
- (d) Sheet erosion
Answer and explanation
Level 3: Mains Answer Writing
Q1. (60 words) What is phytoremediation? Give two examples.
Model answer outline
- Definition: the use of green plants to remove, stabilise or break down pollutants in soil and water; cheap, solar-powered, in situ.
- Examples: Indian mustard (Brassica juncea) absorbing lead and other heavy metals; sunflowers used for radioactive and metal contamination; water hyacinth and reeds in constructed wetlands treating wastewater.
- Limit: slow, and works only within root depth.
Q2. (150–200 words) Noise pollution is often called a “silent killer”. Discuss its effects and evaluate the legal framework to control it in India.
Model answer outline
- Intro: Noise is unwanted sound; its harm builds slowly and unnoticed, hence “silent killer”.
- Effects: hearing loss; hypertension and heart disease; sleep loss and stress; poor learning in children; disturbance to wildlife.
- Legal framework:
- Noise Pollution (Regulation and Control) Rules, 2000 under the EP Act 1986: zone-wise limits (75/65/55/50 by day); silence zones of 100 m; loudspeaker ban 10 p.m.–6 a.m. with a 15-day festive relaxation to midnight.
- Supreme Court, In re: Noise Pollution (2005): freedom from noise is part of Article 21.
- Motor vehicle rules on horns and silencers; green crackers.
- Evaluation: good rules but weak enforcement; limited monitoring outside metros; social acceptance of loud celebrations; low awareness.
- Chhattisgarh angle: DJ systems in festival processions and weddings; district administrations enforce timings and silence zones.
- Way forward: real-time noise monitoring, noise mapping in cities, seizure of offending equipment, awareness campaigns, and urban planning with buffer zones.
- Conclusion: A quieter environment is part of the right to a healthy life.
Quick Revision Table
| Fact | Detail |
|---|---|
| Bioremediation | Microbes; Oilzapper (TERI + Indian Oil) |
| Phytoremediation | Plants; Indian mustard for lead |
| Endosulfan | Supreme Court ban 2011; Kasaragod; Stockholm POP |
| DDT | Banned in agriculture; vector control allowed |
| Soil Health Card | Feb 2015, Suratgarh (Rajasthan) |
| Over-irrigation | Waterlogging and salinisation |
| Decibel | Logarithmic; +10 dB ≈ 10× intensity |
| Noise Rules | 2000, under EP Act 1986 |
| Day / night | 6 a.m.–10 p.m. / 10 p.m.–6 a.m. |
| Limits (day/night) | Industrial 75/70; Commercial 65/55; Residential 55/45; Silence 50/40 |
| Silence zone | ≥ 100 m around hospitals, schools, courts |
| Loudspeakers | Banned 10 p.m.–6 a.m.; up to midnight for ≤ 15 days/year (state) |
| Court | In re: Noise Pollution (2005); Article 21 |
Key Takeaways
- Soil pollution comes from agrochemicals, industry, mining, fly ash and waste; it reaches us through food and groundwater.
- Bioremediation uses microbes; phytoremediation uses plants.
- Balanced fertiliser use (Soil Health Card), IPM and organic farming prevent soil pollution.
- Noise limits: 75/65/55/50 by day and 70/55/45/40 by night; silence zone 100 m.
- Loudspeakers are banned 10 p.m.–6 a.m., with a state-granted midnight relaxation of up to 15 days a year.
What’s Next
- Solid Waste Management, the next topic in this chapter
- Water Pollution, the previous topic
- Light and Sound, for the physics of sound and the decibel scale
- Agricultural Science, for biofertilisers and integrated pest management
- Pollution and Waste — Quick Revision