Every fall, Hindus around the world light lamps, candles, and firecrackers as part of a five-day festival known as Diwali. The celebration, which has roots as a harvest festival, usually falls between mid-October and mid-November. In 2012, it began on November 11.
On November 12, 2012, the Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi NPP satellite captured this nighttime view of southern Asia. The image is based on data collected by the VIIRS “day-night band,” which detects light in a range of wavelengths from green to near-infrared. The image has been brightened to make the city lights easier to distinguish.
Most of the bright areas are cities and towns in India, the country with the world’s largest Hindu population. India is home to more than 1.2 billion people and has 30 cities with populations over 1 million. (For comparison, China has 62 cities with more than 1 million residents and the United States has 9). Cities in Bangladesh, Nepal, and Pakistan are also visible near the edges of the image.
An image that claims to show the region lit for Diwali has been circulating on social media websites and the Internet in recent years. In fact, it does not show what it claims. That image, based on data from the Operational Linescan System flown on U.S. Defense Meteorological Satellite Program (DMSP) satellites, is a color-composite created in 2003 by NOAA scientist Chris Elvidge to highlight population growth over time. In that image, white areas show city lights that were visible prior to 1992, while blue, green, and red shades indicate city lights that became visible in 1992, 1998, and 2003 respectively.
In reality, any extra light produced during Diwali is so subtle that it is likely imperceptible when observed from space.
NASA Earth Observatory image by Jesse Allen and Robert Simmon, using VIIRS Day-Night Band data from the Suomi National Polar-orbiting Partnership (Suomi NPP). Suomi NPP is the result of a partnership between NASA, the National Oceanic and Atmospheric Administration, and the Department of Defense. Caption by Adam Voiland.
Here’s what India looked like to the Suomi NPP satellite during Diwali.