transit visa for trip Kunming - Shanghai - Beijing - Seoul

Hi,

This is our itinerary:

Depart
12:30 AM
Kolkata , India
Netaji Subhas Chandra (CCU)
Stop 1
5:15 AM
Kunming , China
Kunming Airport (KMG)
Change of planes. Time between flights: 4hr 30min

China Eastern Airlines 556
Economy
Boeing 737
2hr 15min
Seat map
Depart
9:45 AM
Kunming , China
Kunming Airport (KMG)
Stop 2
1:00 PM
Shanghai , China
Hongqiao International Airport (SHA) Terminal 2
Change of planes. Time between flights: 19hr 20min

China Eastern Airlines 5805
Economy
Boeing 737
3hr 15min
Seat map
Depart
8:20 AM
Shanghai , China
Hongqiao International Airport (SHA)
Arrive
11:00 AM
Seoul , South Korea
Gimpo International Airport (GMP)

Do we need it to transit? It is about 31 hours in total. Thank-you