This is a file from the Wikimedia Commons. Information from its description page there is shown below. Commons is a freely licensed media file repository. You can help.
Summary
Description2015 PM2.5 Air Pollution Index in Seoul (hourly).png
English: 2015 PM2.5 Air Pollution Index in Seoul (hourly average data
Very Unhealthy
Unhealthy
Unhealthy for sensitive groups
Moderate
Good
Date
Source
Own work Data source:Finalized data download. Korea Environment Corporation. Archived from the original on 2016-10-01. Retrieved on 2016-10-01.
Author
Phoenix7777
Other versions
File:2015 PM2.5 Air Pollution Index in Seoul (hourly) wide.png (Hourly average data)
File:2015 PM2.5 Air Pollution Index in Seoul (hourly).png (Hourly average data)
File:2015 PM2.5 Air Quality Index in Seoul.svg (Daily average data)
Licensing
I, the copyright holder of this work, hereby publish it under the following license:
This file is licensed under the Creative Commons Attribution-Share Alike 4.0 International license.
You are free:
to share – to copy, distribute and transmit the work
to remix – to adapt the work
Under the following conditions:
attribution – You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
share alike – If you remix, transform, or build upon the material, you must distribute your contributions under the same or compatible license as the original.