CPCB Ground-Truth Cleaning Report
- Input:
merged_cpcb_data.csv — 1,549,637 rows, 34 columns
- Output:
merged_cpcb_clean.csv — 972,562 rows, 20 columns
- Net removed: 577,075 rows (37.2%)
Rows removed, by reason
| step |
rows |
| dropped rows with no lat/lon (unusable in node graph) |
26,296 |
| negative concentrations set to NULL |
0 |
| dropped rows where ALL 7 target pollutants are null |
546,277 |
| dropped duplicate (station,lat,lon,date) rows |
4,502 |
Columns dropped (garbage / redundant / met)
SourceFile, FileYear, State_Raw, AT (°C), RH (%), WS (m/s), WD (deg), RF (mm), TOT-RF (mm), SR (W/mt2), BP (mmHg), VWS (m/s), Year, Month
Kept columns
date, station, city, state, state_hint, state_mismatch_flag, geocode_confidence, agency, lat, lon, coverage_area_km2, pm25, pm10, no2, so2, co, o3, nh3, no, nox_ppb
Pollutant coverage after cleaning (non-null %)
| pollutant |
non-null % |
target? |
| pm25 |
93.2% |
yes |
| pm10 |
88.5% |
yes |
| no2 |
96.6% |
yes |
| so2 |
94.1% |
yes |
| co |
94.6% |
yes |
| o3 |
91.7% |
yes |
| nh3 |
80.1% |
yes |
| no |
95.0% |
aux |
| nox_ppb |
96.0% |
aux |
Year coverage
| year |
rows |
| 2009 |
4,057 |
| 2010 |
4,725 |
| 2011 |
6,596 |
| 2012 |
6,700 |
| 2013 |
6,094 |
| 2014 |
5,553 |
| 2015 |
8,524 |
| 2016 |
12,644 |
| 2017 |
18,444 |
| 2018 |
39,186 |
| 2019 |
60,018 |
| 2020 |
76,712 |
| 2021 |
96,640 |
| 2022 |
115,967 |
| 2023 |
156,676 |
| 2024 |
177,757 |
| 2025 |
176,269 |
Geocode confidence (rows)
| confidence |
rows |
| high |
841,064 |
| medium_state_mismatch |
126,158 |
| low_ambiguous |
5,340 |
not_found cities were dropped (no coordinates). Hand-add lat/lon for any that matter: Bileipada, DU Delhi, Kunjemura, Milupara, Palkalaiperur, Suakati, Tumidih.
State mismatches
- 9,588 rows flagged (folder state ≠ geocoded state).
state = geocoded (primary); state_hint = folder; flag kept. Do not auto-resolve — mixed cause: some folder-wrong (Bhilai/Bilaspur/Korba → Chhattisgarh, geocode correct), some geocode-wrong (Chhal, Panchgaon). Manual review needed; coordinates (not state) drive the node graph.
Notes
- Pollutant NULLs are left null (missing ≠ 0). Do not impute; they mask in training.
nox_ppb is in ppb (all others µg/m³, CO in mg/m³) — unit differs, kept separate.- Timestamps treated as IST calendar dates (CPCB is local IST) — aligns with
node_observations_daily date convention.
