43% Increase in Night lights in a decade, upto 440% in some states

While researchers and scientists have been actively using the image of the earth at the night - night time light (NTL) - to reckon the human activity and natural events for over three decades, economists, too have followed suit in recent years, realising how this can help gauge a variety of indicators.

An IMF publication on ‘how satellite images at night reveal the pace of economic growth and much more' reads, "Infact, if aliends were to approach Earth from its dark side, they would know some basics about the global economy. "

Night time light

Viewing nighttime lights provides a unique perspective of the planet. Unlike daytime remote sensing, there are multiple sources of nighttime illumination. These sources include moonlight, light directly emitted by a source (e.g., buildings and transport), and light reflected by the ground, also known as surface albedo.

ISRO's National Remote Sensing Centre (NRSC), released Decadal Change of NTL over India from Space (2012-2021), shows an overall normalised NTL radiance increase by 43% in 2021 in comaparison with 2012.

To reckon the data, NRSC uses data from NASA and NOAA (National Oceanic and Atmospheric Adminstration) and NTL  provided is the cumulative radiance divided by the total geographical area. That is, nationally it is for the geographical area of theentire country and for states and districts, it’s those res pective administrative boundaries. 

As developed states like, Maharashtra, Karnataka, Tamil Nadu, Andhra-Telangana, already have a higher base number in 2012, therefore the percentage increase is moderate with only 55%, While lesser developed states have recoreded a higher growth percentage.

According to Atlas, "Bihar (474%), Manipur (441%), Ladakh (280%) and Kerala (119%) on the other hand, there was a good increase observed in Gujarat (58%), Uttar Pradesh (61%),  Arunachal Pradesh (66%) and Madhya Pradesh (66%).

Moderate increase was observed in Assam, Andaman and Nicobar Islands, Chhattisgarh, Chandigarh, Goa, Himachal Pradesh, Haryana, Odisha, Jharkhand, Jammu & Kashmir, Karnataka, Lakshadweep, Maharashtra, Nagaland, Odisha, Punjab, Telangana, Tripura, Uttaranchal, West Bengal. 

Although the rise in six states and two UTs has been deemed small, the increase in 21 states and two UTs is between 6% and 40%. (see graphic). "NTL stands for artificial light intensity, which has a number of development-related implications.
Sensors aboard NASA and NOAA flights together provide the NTL data.

These outputs may be utilised for spatiotemporal trend analysis to discover how it relates to environmental changes and socioeconomic factors like GDP, population, urbanisation, poverty, and power consumption "NRSC Director Prakash Chauhan remarked.

The World Bank, Asian Development Bank (ADB), and other institutions and organisations throughout the world are increasingly using nighttime satellite photos to interpret various socio-economic variables. It's not just the IMF that does this.

NTLs, according to the ADB and the World Bank, are much more than just ornaments; they contain data that may be used to calculate socioeconomic indicators in cases when no other trustworthy sources of information are available.