A corruption of smoke and dust will be seen before the coming of Hazrat Mahdi (as)
This hadith came totally true on 11 September, 2001, with the worst ever terror attacks on New York and Washington in the USA. As the whole world saw, a big, thick cloud of dust and smoke swallowed up the immediate surroundings.
Corruptions (fitna) will follow one another in the near future. Then, there will be other corruptions and even more following them. (Al-Muttaqi al-Hindi, Al-Burhan fi Alamat al-Mahdi Akhir az-Zaman, p. 26)
It will be remembered that a huge cloud of smoke rose up because of the explosion caused by the airplanes as they crashed into the towers, and that smoke rose high enough to be seen from great distances away. And the collapse of the towers in the wake of the explosions gave rise to an even greater cloud of dust, totally covering the people and streets all around.
This was one of the worst terrorist atrocities in history, and since it took place at a time when the portents of the End Times are all happening one after the other and in complete agreement with the description in the hadith, it is also one of the signs of the coming of Hazrat Mahdi (as). Allah knows the truth.