Haze and the Sun

It was 5.30pm, yet the sun was so obscured, blocked by the haze caused by human burning.
So the theory of mass extinction of many living things in the past seems logical. If there was a huge meteorite impact on Earth or super-volcanic eruption, the sun would likely be totally blocked by fire and dust, there would not be light for many days or even months, then the survival of many living things would be in jeopardy. 
Perhaps, that was why intelligent animals only came to Earth's scene so late, before they could form, they were already wiped off!