Small bikes like these already have so low emission that they are complaint may be Euro-IV or may be CD 70 is also already complaint to EURO V Toxic Emission Standards.
Have Look :
- Euro 1 (1993):
- For passenger cars - 91/441/EEC.[SUP][/SUP]
- Also for passenger cars and light trucks - 93/59/EEC.
- Euro 2 (1996) for passenger cars - 94/12/EC (& 96/69/EC)
- For motorcycle - 2002/51/EC (row A)[SUP][/SUP] - 2006/120/EC
- Euro 3 (2000) for any vehicle - 98/69/EC[SUP][/SUP]
- For motorcycle - 2002/51/EC (row B)[SUP][/SUP] - 2006/120/EC
- Euro 4 (2005) for any vehicle - 98/69/EC (& 2002/80/EC)
- Euro 5 (2008/9) and Euro 6 (2014) for light passenger and commercial vehicles - 715/2007/EC[SUP][/SUP]
At the level of 125cc engines they have to put emission controllers to make an engine complaint to policies smaller then 125 are already low emission engines, so as you said they will be changing stickers only. 
Ref:
European emission standards - Wikipedia, the free encyclopedia