Changes in version 0.3.0                        

Breaking changes

  - CPCB station lists come from a bundled directory and work offline.
  - Live AQI holds only the latest hour: date, hour and date_time are
    ignored with a warning; last_hours is removed.
  - pm25_download_netcdf() fetches V6.GL.03 (1998-2024) from the AWS
    satpmdata bucket; the v6.gl.02.04 bucket is gone.
  - Downloads are cached in vayuayan_cache_dir(); files in the Python
    package's cache are reused.
  - pm25_v5gl04_monthly() is now pm25_monthly(version = "V5GL04").
  - cpcb_get_file_path() returns CPCB's entries as sent: filepath (was
    filePath) and year as CPCB gives it.

New features

  - theme_vayuayan() (the ggplot2 theme of the package's figures) and
    plot_sensor_vs_reference().
  - compute_us_aqi(), us_aqi_sub_index(), us_aqi_category(),
    us_aqi_color() and us_aqi_pollutant_name() calculate the US EPA AQI
    with the May 2024 EPA tables. Labels with a mass unit, such as "O3
    (ug/m3)", are converted to ppm or ppb at 25 degrees C.
  - CPCB National AQI: compute_aqi(), aqi_sub_index(), daily_aqi().
    Above the Severe band the sub-index continues on the same slope, as
    in CPCB's AQI calculator, and the AQI is rounded half up.
  - Raw and hourly CPCB data: cpcb_download_raw_station_data(),
    cpcb_download_hourly_city_data(),
    cpcb_download_hourly_station_data(), cpcb_raw_to_long(),
    cpcb_station_daily_aqi().
  - Daily data in long form: cpcb_tidy_daily(), cpcb_city_daily(),
    cpcb_station_daily().
  - Stations can be given by name or a unique part of it ("Anand Vihar,
    Delhi"), not just ID.
  - cpcb_get_nearest_stations() and stations_to_city_summary().
  - PM2.5 functions take version ("V6GL03", "V6", "V5", "V5GL04") and
    region ("AS" for the smaller Asia files).
  - pm25_get_point(), pm25_get_stats_by_polygon(), pm25_monthly().
  - india_boundary() and pm25_map().
  - oaq_stations_table(); oaq_fetch_monthly_stations() takes several
    providers.
  - OAQ sensor tools: oaq_sensors(), oaq_readings(), oaq_daily_means(),
    oaq_daily_records(), oaq_check_daily_records(), oaq_nearest_cpcb(),
    oaq_city_tally(); cpcb_raw_readings() for several stations.
  - OAQ daily records: compare_daily_records(), daily_record_summary(),
    oaq_audit_daily_records() and the plot_daily_record_*() figures
    (ggplot2).
  - Sensor quality checks against the US EPA targets for PM2.5 sensors:
    readings_mean(), sensor_completeness(), sensor_plausibility(),
    collocated_precision(), peer_ratio(), sensor_accuracy(),
    ratio_by_humidity().
  - aqi_health_impact(), aqi_pollutant_category(), cpcb_live_to_long()
    and cpcb_live_metrics().

Bug fixes

  - OAQ responses with bare NaN values (some daily files of 2025) are
    read with NA; before, oaq_readings() and the functions that use it
    left those days out.
  - oaq_fetch_monthly_stations() failed when providers return different
    columns or id types; oaq_get_city_latest() needs a lower-case city
    in OAQ's paths and now lower-cases it; OAQ data requests are retried
    after network errors and 5xx statuses. The OAQ examples use real
    sensors.
  - get_aqi_categories() returns character(0) for empty input.
  - analyze_station_data() counted columns instead of cities.
  - Interrupted PM2.5 downloads no longer leave partial files in the
    cache.

Other changes

  - Dropped geosphere, glue and lubridate, and the startup message.
  - Station, state and city lists sort in C-locale order; cities of the
    live feed sort by share of live stations, then name. Hourly readings
    are numeric. PM2.5 std divides by n (population standard deviation
    of the grid cells).
  - Analysis vignettes moved to pkgdown articles.