Today evening when I came out of office by around 7:15 pm, I saw a trail of smoke made by a jet. I was watching the line as it was slowly getting thin due to wind. Then all of a sudden I could see a white object crossing the smoke trail at a high altitude compared to the trail. I could notice it due to a shine from the sunlight & since the sky was clear. I am not sure if it is a plane/satellite/ISS. It was not static & moving at a good speed. In the limited knowledge I have about airplanes, i think the max height they travel is 30k feet when it makes the smoke trail. but this object was high above that.