The BBC has an article with photos of celebrities in front of the Taj Mahal over the decades. The thing that caught my eye was how the sky is nearly never blue in the recent photos. While the yellowing of the Taj’s marble is well documented, the slow yellowing of our sky is well known but rarely discussed (GDP growth trumps everything else).
Here are the photos, chronologically arranged:
Of course this set is in no way representative. They are too few data points. All susceptible to the weather on the day, the camera settings, and the post processing.
There is also a bit of confirmation bias on my part. I’ve noticed, sadly, the disappearance of blue day skies and starry night skies for over two decades. And I probably looked at the photos to confirm that.
But this also gives an idea that this may not be the worst approach. There are probably billions of photos shared of the Taj on social media every year. We could create a program that scans for them, dates them, filters out the outliers, and then analysis the trend of sky colour (and Taj’s marble colour) over time. Time to put all that social media oversharing to good use :)