December in the country of Sweden is a time of darkness. Its capital city of Stockholm received only half an hour of sunlight in the first half of this month, putting it on track for the darkest December since 1934, meteorologists said, according to Agence France-Presse.

The nighttime condition is normal because of Sweden’s location in the northern hemisphere. 

During the month of December, that region of the earth is tilted away from the sun causing it to take a very low path across the sky, or not rise at all in far northern areas.

After the winter solstice, daylight increases in Sweden by a few minutes each day and by March, day and night are nearly equal again. 

Meanwhile, a startup firm based in California, USA is selling $1 balloons containing sulfur dioxide (SO2), the same material expelled by erupting volcanoes. 

Make Sunset founder Luke Iseman then brings 1,000 of the balloons to the hills half an hour outside Saratoga and releases them there, The Washington Post (TWP) reports. 

When the balloons burst in the stratosphere, the released SO2 would block sunlight from reaching the ground, a solar geo-engineering method to cool the planet, according to TWP. 

However, the miniscule amount of SO2 may not produce the cooling effect. 

When Mount Pinatubo in the Philippines erupted in 1991, it released millions of tons of SO2 that reportedly reduced global temperatures by about half a degree for roughly a year. 

Nevertheless, Make Sunsets has raised more than $1 million from investors and sold more than $100,000 worth of “cooling credits” to customers this year, according to TWP.