Achieving all the above objectives causes changes on 
three  essential  and  specific  elements  of  sustainable 
development,  namely  the  economy,  the  natural 
environment and society. This view is also supported 
by  Mensah  (2019)  who  states  that  "sustainable 
development  is  based  on  economic  sustainability, 
environmental  sustainability  and  social 
sustainability", but also by Munasinghe (1993) who 
stated that sustainable development can be seen from 
three  points  of  view,  namely  economic,  social  and 
ecological.  From  this  point  of  view,  the  field  of 
tourism  falls  within  the  scope  of  sustainable 
development, as it involves economic aspects (jobs, 
wages,  etc),  and  environmental  issues  (natural 
resources),  but  also  social  aspects  (strengthening 
cultural  identity  of  tourist  destinations,  poverty 
reduction,  etc).  Bâc  (2013)  states  that  the  basis  of 
sustainable  society  is  the  principle  of  equitable 
distribution  and  democratic  participation.  The 
principle of equitable  distribution  affects  resources, 
as  it  refers  to  their  fair  distribution.  Democratic 
participation  is  a  principle  that  emphasizes  the 
importance and need for society / people to take part 
in the decision-making process. 
In accordance with the definitions of tourism and 
sustainable  development,  the  notion  of  sustainable 
tourism has appeared in the literature, in the sense that 
this  notion  can  be  seen  as  "the  application  of  the 
principles  of  sustainable  development  in  tourism" 
(Bâc,  2013).  Given  that  tourism  also  has  negative 
effects  on  society  (erosion  of  local  traditions, 
congestion,  etc)  and  the  environment  (pollution, 
irresponsible  and  continuous  consumption  of  local 
resources, etc), we can admit that it was imperative to 
find  solutions.  Against  the  background  of  the 
negative  aspects  of  tourism,  the  concept  of 
sustainable tourism appeared. Bâc (2013) admits that 
"sustainable tourism is a reactive notion, which aims 
to  eradicate  the  negative  impact  of  tourism".  This 
approach aims at the goal of sustainable tourism. A 
holistic approach to defining the concept is provided 
by  the World Tourism Organization  and  the United 
Nations  Environment  Program,  which  have 
formulated  the  following  definition:  "Sustainable 
tourism  is  the  type  of  tourism  that  focuses  on  its 
present and future socio-economic situation"(United 
Nations  Environment  Programme  and  World 
Tourism Organization, 2005). The two international 
authorities  highlighted  the  fact  that  sustainable 
tourism  falls  under  the  umbrella  of  sustainable 
development, through the prism of tourists, industry, 
environment and communities that fall into the main 
components  of  sustainable  development:  economy, 
society and environment. 
All  forms  of  tourism  can  enter  the  sphere  of 
sustainable  tourism  (Ioan,  Rădulescu,  &  Cojocea, 
2012),  but  there  are  also  several  distinct  forms, 
including  ecotourism,  rural  tourism,  pro-poor-
tourism  (Bâc,  2013).  In  addition  to  these  forms  of 
tourism, other ones have been studied in the literature, 
for example  volunturism, which in recent years has 
seen  an  upward  trend  (Pompurova,  Marcekova, 
Sebova, Sokolova, & Zofaj, 2018)or cultural tourism, 
which  Zoran  (2018)  concludes  that  "is  a  form  of 
tourism that educates people about the history, art and 
architecture of a tourist destination." Also, Zargham 
(2007)  considers  that  cultural  tourism  is  one  of  the 
most  intense  forms  of  sustainable  tourism,  because 
through the interest of tourists for this form of tourism 
is stimulated the reconditioning of historical vestiges. 
The study of sustainable tourism indicators is not 
a  new  topic  in  the  literature.  Given  the  fact  that 
sustainable  tourism  can  be  approached  through  the 
prism of sustainable development pillars (economic, 
social,  environmental),  its  indicators  can  be 
categorized  according  to  these  pillars,  a  special 
importance  having  the  environmental  pillar.  For 
example, Lozano-Oyola et al. (2012) includes in the 
environmental pillar several indicators of sustainable 
tourism,  including:  ,,  percentage  of  protected  areas, 
percentage  of  energy  consumption  from  renewable 
sources, amount of waste produced at a destination, 
density of buildings, noise level during the day , the 
number of tourists in an area etc''. 
2.2  Overtourism 
From  an  economic  point  of  view,  the  numerous 
tourist flows have advantages for local entrepreneurs, 
at least in terms of revenues. That is the reason why 
most  local  entrepreneurs  show  a  positive  attitude 
towards  tourists  and  make  considerable  efforts  to 
increase  their  number.  At  the  same  time,  the  large 
number  of  tourists  from  a  tourist  destination  brings 
advantages for the local population, in the sense that 
a large number of tourists generates the need for staff, 
which  leads  to  new  jobs.  This  is  an  optimistic 
approach  to  the  impact  that  tourism  can  have  on  a 
tourist  destination,  but  there  is  also  a  pessimistic 
approach that can be described in terms of the concept 
of  overtourism. 
According  to  the  World  Tourism  Organization, 
overtourism  is  "the  impact  that  tourism  has  on  a 
tourist destination and that negatively influences the 
quality  of  life  of  residents  and  the  experiences  of 
tourists"(World  Tourism  Organization,  2018).  By 
comparison,  overtourism  is  the  antithesis  of 
sustainable tourism, as the latter positively influences