From this map you can see the way KYIV is gradually being...

From this map you can see the way KYIV is gradually being surrounded. Putin needs Kyiv for logistic reasons more than political.
Early in the war Ukraine blew up the rail lines into Ukraine . This has forced the Russians to use trucks . It appears that they had been hoping for a quick victory and to do resup down the train lines Kyiv has a number of airstrips and road junctions .