Asian mega-smog's smoky source in Sumatra
I don't know what I was expecting, but it was certainly something spectacular.
Given the volume of smog that has been spewed across Singapore and Malaysia in the last few days, it would have to be something big.
But after eight hours driving along terrible roads, with even worse traffic, I was starting to doubt my own sanity.
"Where can all this smoke be coming from if there are no fires?"
In fact we had seen fires, or at least their aftermath. Dozens of them, little blackened patches of land, some just a few square meters.
In my mind there was no way such weedy fires could have caused the "mega smog".
Then just before sunset, somewhere north of the city of Dumai we found it: mile after mile of charred blackened land, the smoke still rising, the earth still hot underfoot.
A gust of wind, and the flames leaped up again from smouldering tree stumps. The air was thick, acrid and unbreathable.
But even here anyone expecting to see spectacular forest fires would be disappointed.
The truth is these are not really forest fires at all. The forest has already been cut for timber.
This is land clearance by fire, classic slash and burn, but on a much larger scale.
Who is doing it? Certainly not anyone I spoke to.
Everybody here knows it is illegal and controversial, so everyone blames someone else.
The farmers blame the oil palm corporations. The corporations blame the farmers.
But the truth is everyone is doing it. Burning is a way of life in Sumatra.
One local woman, whose house has been damaged by the fires, was disarmingly honest about what goes on.
"The farmers burn the forest all the time," she said. "They burn it so the land can be planted.
"The trouble is this time, because of the very dry weather and high winds, the fires have got out of control."
Just 20 or 30 years ago, eastern Sumatra was covered by a huge swamp forest. Today there is barely any left.
Instead, on our eight-hour drive from Pekanbaru to Dumai the forest has been replaced entirely by a massive monoculture: mile after mile after mile of oil palm plantation.
It is a huge industry: the oil is in high demand from the food industry, cosmetics, even for biofuel. Now there's an irony.
Indonesia is now the word's biggest producer of palm oil, more than 20 million tonnes per year. And Sumatra is its new frontier.
The people who have come here, both the corporations and the farmers, are looking for new land to open up.
There is little romance about the loss of the rainforest, or its wildlife.
It is all about money. Greed and conservation have never made good bedfellows.