NAAQS 2009 air quality limits for all 12 pollutants in India
India's NAAQS 2009 sets ambient limits for 12 pollutants. See the full limits table, monitoring rules and comparison with WHO air quality guidelines.
NAAQS stands for National Ambient Air Quality Standards. India's NAAQS 2009 schedule sets ambient-air concentration limits for 12 pollutants, with defined averaging periods and area categories. The annual limits for PM2.5 and PM10 are 40 and 60 µg/m³, respectively. These values come from CPCB's reproduction of the 2009 standards, Table 1.1.
Use this page as a reference to the 2009 schedule. For a formal compliance assessment, check the latest CPCB notification and the requirements that apply to your site. A table of concentration limits alone cannot establish a facility's compliance.
NAAQS 2009 limits for all 12 pollutants
The table below reproduces the values in CPCB Table 1.1, printed pages 1–2. Values separated by a slash follow the same order as the averaging periods. For example, PM10's general-area values are 60 µg/m³ annually and 100 µg/m³ over 24 hours.
"General areas" covers industrial, residential, rural and other areas. "Sensitive areas" means ecologically sensitive areas notified by the Central Government. A rural location does not qualify for that column just because it appears environmentally sensitive.
| Pollutant | Unit | Averaging period | General areas | Sensitive areas |
|---|---|---|---|---|
| Sulphur dioxide (SO₂) | µg/m³ | Annual / 24 hours | 50 / 80 | 20 / 80 |
| Nitrogen dioxide (NO₂) | µg/m³ | Annual / 24 hours | 40 / 80 | 30 / 80 |
| PM10 | µg/m³ | Annual / 24 hours | 60 / 100 | 60 / 100 |
| PM2.5 | µg/m³ | Annual / 24 hours | 40 / 60 | 40 / 60 |
| Ozone (O₃) | µg/m³ | 8 hours / 1 hour | 100 / 180 | 100 / 180 |
| Lead (Pb) | µg/m³ | Annual / 24 hours | 0.50 / 1.0 | 0.50 / 1.0 |
| Carbon monoxide (CO) | mg/m³ | 8 hours / 1 hour | 2 / 4 | 2 / 4 |
| Ammonia (NH₃) | µg/m³ | Annual / 24 hours | 100 / 400 | 100 / 400 |
| Benzene | µg/m³ | Annual | 5 | 5 |
| Benzo(a)pyrene, particulate phase only | ng/m³ | Annual | 1 | 1 |
| Arsenic (As) | ng/m³ | Annual | 6 | 6 |
| Nickel (Ni) | ng/m³ | Annual | 20 | 20 |
Watch the units. Carbon monoxide uses milligrams per cubic metre, while benzo(a)pyrene, arsenic and nickel use nanograms per cubic metre. The other pollutants use micrograms per cubic metre. Labelling the entire table "µg/m³" would give the wrong limits for four pollutants.
Only the annual SO₂ and NO₂ limits differ between the two area columns. The sensitive-area annual limits are 20 µg/m³ for SO₂ and 30 µg/m³ for NO₂. Their 24-hour limits remain 80 µg/m³ in both columns, as shown in the CPCB schedule.
For an air quality standards PDF, CPCB also hosts the Gazette document. The numerical reference used here is the CPCB report linked above.
How to read the monitoring rules
Start with the pollutant and unit, then match the measurement's averaging period to the correct row. Select the applicable area column before applying the monitoring rules. Comparing an annual mean with a 24-hour limit does not answer whether either standard was met.
Annual means need a sampling record
The annual mean is the arithmetic mean of at least 104 measurements per year at a particular site. The schedule specifies twice-weekly, 24-hourly measurements taken at uniform intervals. These are not 104 instantaneous sensor readings. The definition appears in the annual footnote to CPCB Table 1.1.
Keep the sampling record with the annual result. A reported yearly average, without its measurement schedule, does not show whether this sampling definition was followed. When reviewing a monitoring report, check the number of measurements and their spacing, rather than accepting the label "annual" alone. Review short-period results separately, using their own averaging periods and limits. An annual average below the limit does not prove that each short-period value complied.
The 98% rule has a condition
Applicable 24-hour, 8-hour or 1-hour monitored values must meet the limits 98% of the time in a year. The remaining 2% may exceed them, but not on two consecutive days of monitoring. Both parts appear in CPCB's short-period footnote.
Don't convert that wording into a fixed allowance of calendar days. The record must preserve when monitoring took place and whether exceedances occurred on consecutive monitoring days. A percentage alone leaves that second question unanswered.
CPCB's accompanying note identifies exceedances on two consecutive monitoring days as grounds for regular or continuous monitoring and further investigation. It does not establish an automatic shutdown or a universal penalty in that table. Keep the monitoring note separate from any site-specific enforcement assessment.
Indian air quality standards compared with WHO guidelines
WHO's 2021 recommended air quality guideline levels are lower than NAAQS 2009 for several matching pollutant-period pairs. The table compares India's general-area limits with WHO's recommended levels, not WHO interim targets. Sources are CPCB Table 1.1 and WHO Table 0.1.
| Pollutant | Averaging period | NAAQS 2009 | WHO 2021 recommended level |
|---|---|---|---|
| PM2.5 | Annual | 40 µg/m³ | 5 µg/m³ |
| PM2.5 | 24 hours | 60 µg/m³ | 15 µg/m³ |
| PM10 | Annual | 60 µg/m³ | 15 µg/m³ |
| PM10 | 24 hours | 100 µg/m³ | 45 µg/m³ |
| NO₂ | Annual | 40 µg/m³ | 10 µg/m³ |
| NO₂ | 24 hours | 80 µg/m³ | 25 µg/m³ |
| SO₂ | 24 hours | 80 µg/m³ | 40 µg/m³ |
| O₃ | 8 hours | 100 µg/m³ | 100 µg/m³ |
India's annual PM2.5 limit is eight times WHO's recommended concentration. For annual PM10, the ratio is four. These ratios compare concentration values. They do not describe multiples of health risk.
The matching ozone values also need care. Both tables show 100 µg/m³ for eight hours, but equal concentrations do not establish identical compliance rules. WHO's short-term table includes a 99th-percentile footnote, approximately three to four exceedance days per year. That is distinct from India's qualified 98% rule. See WHO's explanation of the guideline tables.
WHO states that its guidelines are not legally binding. They inform policy and legislation, rather than automatically replacing Indian standards. Keep the legal-standard comparison separate from the health-based guideline comparison in a monitoring report.
Are these PM2.5 safe levels or an AQI standard?
For PM2.5 safe levels or PM10 safe levels, specify which benchmark you mean. NAAQS 2009 gives annual and 24-hour limits. WHO provides different recommended levels for those same periods. Neither should be presented as a promise of risk-free exposure. Use the WHO guideline table when making that distinction.
This schedule does not answer "What is a normal AQI level in India?" It lists ambient concentrations with units and averaging periods, not today's AQI. It is also not a stack-emission-limit table. Use the CPCB ambient standards for the question they address: which concentration limit applies to the measured pollutant and period?
RegAffairs AI's answer on India's ambient air quality standards brings the limits and WHO comparison together.