![A rainbow appears in the sky after rainfall in Bangkok, Thailand, Feb. 17, 2019. The rainfall helped to improve the air quality in Bangkok. (Xinhua/Zhang Keren)](http://www.ecns.cn/hd/2019/02/18/b85af84306864520b36e81bdc9152a36.jpg)
A rainbow appears in the sky after rainfall in Bangkok, Thailand, Feb. 17, 2019. The rainfall helped to improve the air quality in Bangkok. (Xinhua/Zhang Keren)
![A rainbow appears in the sky after rainfall in Bangkok, Thailand, Feb. 17, 2019. The rainfall helped to improve the air quality in Bangkok. (Xinhua/Zhang Keren)](http://www.ecns.cn/hd/2019/02/18/225fcc9fa86f43bb9d09ae376d8c7cdf.jpg)
A rainbow appears in the sky after rainfall in Bangkok, Thailand, Feb. 17, 2019. The rainfall helped to improve the air quality in Bangkok. (Xinhua/Zhang Keren)
![The photo shows King Power MahaNakhon skyscraper under a clear sky after rainfall in Bangkok, Thailand, Feb. 17, 2019. The rainfall helped to improve the air quality in Bangkok. (Xinhua/Zhang Keren)](http://www.ecns.cn/hd/2019/02/18/9cd1fcebcd804ed18b50c5bb9427f38f.jpg)
The photo shows King Power MahaNakhon skyscraper under a clear sky after rainfall in Bangkok, Thailand, Feb. 17, 2019. The rainfall helped to improve the air quality in Bangkok. (Xinhua/Zhang Keren)
![The photo shows King Power MahaNakhon skyscraper in sunset after rainfall in Bangkok, Thailand, Feb. 17, 2019. The rainfall helped to improve the air quality in Bangkok. (Xinhua/Zhang Keren)](http://www.ecns.cn/hd/2019/02/18/2871eb3acbad46d198febf02805ba37d.jpg)
The photo shows King Power MahaNakhon skyscraper in sunset after rainfall in Bangkok, Thailand, Feb. 17, 2019. The rainfall helped to improve the air quality in Bangkok. (Xinhua/Zhang Keren)
![The photo shows King Power MahaNakhon skyscraper under a clear sky after rainfall in Bangkok, Thailand, Feb. 17, 2019. The rainfall helped to improve the air quality in Bangkok. (Xinhua/Zhang Keren)](http://www.ecns.cn/hd/2019/02/18/4feb8dbbc06e488e8def3c2b69d7fb76.jpg)
The photo shows King Power MahaNakhon skyscraper under a clear sky after rainfall in Bangkok, Thailand, Feb. 17, 2019. The rainfall helped to improve the air quality in Bangkok. (Xinhua/Zhang Keren)
![The photo shows King Power MahaNakhon skyscraper under a clear sky after rainfall in Bangkok, Thailand, Feb. 17, 2019. The rainfall helped to improve the air quality in Bangkok. (Xinhua/Zhang Keren)](http://www.ecns.cn/hd/2019/02/18/063e43321a384e4b95966454f4cb82ea.jpg)
The photo shows King Power MahaNakhon skyscraper under a clear sky after rainfall in Bangkok, Thailand, Feb. 17, 2019. The rainfall helped to improve the air quality in Bangkok. (Xinhua/Zhang Keren)
![The photo shows King Power MahaNakhon skyscraper in sunset after rainfall in Bangkok, Thailand, Feb. 17, 2019. The rainfall helped to improve the air quality in Bangkok. (Xinhua/Zhang Keren)](http://www.ecns.cn/hd/2019/02/18/209dd6c1895f4f63b8172989bd52cb9b.jpg)
The photo shows King Power MahaNakhon skyscraper in sunset after rainfall in Bangkok, Thailand, Feb. 17, 2019. The rainfall helped to improve the air quality in Bangkok. (Xinhua/Zhang Keren)