No permanent sam base in arunachal. And quite sure about this until proven wrong. Ad hoc deployments are there but you know what it means. What we lack is initiative. If we have initiative we can achieve a lot withstanding all the infra disadvantage we have. And the reason why I highlight this is because we need to have things in place as per our objectives. But what we are doing is reacting to Chinese initiatives. We construct roads when chinks knock. ICBR projects are one of the slowest in the country unfortunately. These are roads that should have been developed in the 80s so we are lagging by quite a margin. Also one of the reason why we get overwhelmed by Chinese patrols most of the times.
Permanent deployment of short-range SAMs only in Arunachal. But that is because permanent deployment only happens if there is a critical infrastructure (like an airbase or army HQ).
I have seen the unfortunate situation of NE (used to formerly live there), and appalling neglect towards basic infrastructure thanks to the ruling govt. only caring for northern and north-western states where the majority of the Indian population resides.
Only in the last 10 years, I have seen some break-neck pace of development, as the govt. woke up from slumber and realized its mistake.
For China, it has been easier because the Yangtse river valley & Nyngchi, north of Arunachal Pradesh has been a hotspot of the population since ancient times, hence their infrastructure and footfall are naturally higher, whereas remote Arunachal valleys have extremely tiny population density.
Similarly opposite is the case for H.P, Sikkim and Uttrakhand for us where we have more population density and naturally better connectivity than China in some sectors. These remote Tibetian areas have nothing but nomads on the Chinese side hence they too did not care for much infrastructure on their side.
Good thing is, within the next 5 years we will be in a hopeful situation to counter and push back Chinese encroachment at every place at LAC.