Services by government to another government

As per entry no. 8 of the notification no. 12/2017 CT (R) dated 28.06.2017, "services by government to another government is exempt, but this exemption will not apply to services referred in clauses (a), (b) and (c) of entry no. 6 of the said notification". So, does this mean that the supply of "services by department of posts, services in relation to aircraft or vessel and services of transport of goods/passengers referred in clauses (a), (b) and (c) of entry no. 6" by government to another government is leviable to GST ?