These are  six (6) class suits against the City Engineer of  Manila to enjoin .him  from carrying out  his threat to  demolish  the houses  of petitioners herein,  upon  the ground that said  houses constitute public nuisances.   In due course,  the Court of  First Instance of Manila rendered separate, but  substantially  identical, decisions  adverse to  the petitioners, who have  appealed  therefrom directly  to  this Court.  Inasmuch as the fact  are  not disputed  and the  same issues  have  been  raised in  all these cases,  which were jointly heard before this Court, we deem it  fit to dispose of the appeals  in one decision.

1. Case No.  L-8191  (Case  No. 21530  of  the  Court of  First Instance of Manila) was instituted by Diosdado A.  Sitchon, Luis Gavino and Ponciano Adoremos, in their own behalf  and  in representation of twenty-two  (22) persons,  named  in an annex  to  the petition.  In  1947 and  1948, said petitioners occupied portions of  the  public street known as Calabash Road, City of Manila, and constructed houses thereon, without  the  consent  of the authorities.  Later on, some of, them paid  "concession fees or  damages, for the use"  of said portions' of the street, to  a collector  of  the city  treasurer,  who issued  receipts with an  annotation reading: "without  prejudice to the order to  vacate."  On or about July  5,  1952,  respondent City Engineer  advised and  ordered  them  to  vacate the place and remove their houses  therefrom before August 5,  1952, with the warning that otherwise  he would effect the demolition  of  said houses  at their  expense.  This notice  having been  unheeded, a demolition team of the office  of the City Engineer informed the petitioners in December, 1953, that  their, houses  would be  removed, whereupon the case was instituted for the  purpose already stated.  At the  instance of  petitioners  herein, the lower court issued a writ  of  preliminary injunction.
   
   
2. Case  No. L-8397  (Case No.  21755 of the Court of First Instance of Manila)  was brought by Ricardo de la Cruz,  Isidro  Perez   and   Fernando  Figuerroa,  in  their behalf and in representation of two  hundred^$ixty-seven (267)  persons,  who, sometime after  the  liberation of Manila,  occupied  portions  of  Antipolo  and  Algeciras Streets,  of said city,  and  constructed  houses  thereon, without any authority therefor.'  Several  petitioners later paid "concession fees or  damages" to  a  collector of the city treasurer, and were  given receipts with  the annotation:  "without  prejudice  to the order to vacate."   The constructions  were   such  that the  roads and  drainage on  both sides thereof were obstructed.   In  some places, the ditches used for drainage purposes  were completely obliterated. What is more, said ditches cannot be opened, repaired  or placed  in  proper condition  because  of  said houses.  On  or about  Slay 15,  1952,  respondent.  City Engineer advised  them to vacate the  place  and remove their houses  within  a stated period, with the  warning already referred to.  Hence, the institution of the case, upon the filing of which a writ  of preliminary injunction was issued.
   
   
3. Felino Peña, Francisco  Morales  and  Jose Villanueva filed case  No. L-8500  (Case No.  21535  of the  Court of First Instance of Manila),  on their own behalf and in representation of  about thirty (30)  persons, who,  without  the aforementioned  authority, occupied  portions of the street area of  R.  Papa Extension,  City of Manila, sometime after  its liberation.  As in the  preceding cases, several petitioners  paid  "concession fees or damages" .to a  collector  of  the  city  treasurer,  "without prejudice to the order to vacate", which was given on May 10, 1932, with  the  warning  that  should  they  fail to remove said houses, respondent  would do so, at their expense.  Upon being advised,  later on,  of the intention of respondent's agents to carry out said threat, the  corresponding petition was filed and a writ  of preliminary injunction  secured.
   
   
4. Santiago Brotamonte,  Godofredo Blanquiso and Salvador  Justiniano commenced case No. L-8513 (Case  No. 21531  of the Court of First Instance of  Manila),  on their behalf and in representation of forty-two (42) other, persons,  who,  without any authority,  occupied  portions  of the bed of  a branch of  the Estero de  San, Miguel, City of Manila,  and constructed  houses thereon, sometime in 1947 and  1948.  As in the cases already mentioned, some of them paid concession  fees or damages, "without prejujudice to  the order to  vacate", which  was  given, with the usual warning, in December,  1953.  The institution of the case and a writ of preliminary injunction soon followed.
   
   
5. In case No. L-8516  (Case No. 21580 of the  Court of First  Instance  of  Manila), Ernesto  Navarro,  Pablo Salas and Herminigildo  Digap are petitioners, on their own behalf and in that of fifteen  (15) persons, who, sometime  after the liberation   of Manila,  occupied portions  of the bed of the Pasig River, at about  the end of Rio Vista Street, San Miguel, Manila, which are covered and uncovered by the tide, and erected houses thereon without  any authority  therefor.   "Concession  fees  or damages" were paid by some of them, "without prejudice to the  order to vacate".  After giving, on or about June 20,  1952,  the corresponding notice and warning, which were not  heeded, respondent threatened to  demolish said houses at petitioners'  expense,  whereupon  the  case was instituted and  a writ  of preliminary  injunction  secured.
   
   
6. Case No. L-8620  (Case No. 22143 of the  Court of First  Instance  of  Manila)  was  filed  by  Amado  Sayo, Marciano  Laraeo and Victor  Bernardo, on their behalf 'and in that of  twenty-two  (22)  other persons,  who, in 1946 and 1947, occupied  portions' of Torres  Bugallon, Cavite,  Misericordia and Antipolo Streets, in  the City of  Manila, and  constructed houses thereon, without any authority  therefor.  Some  paid "monthly  rentals and/or damages, and/or concession fees" from 1946 to 1951, "without prejudice to the order to vacate", which was given on  lay 1, 1952, with the usual warning, followed,.about two (2) years later, by a threat to demolish said houses, Hence, the case,  upon  the filing of  which writ  of preliminary injunction was  issued.
   

After appropriate proceedings, the  Court of  First  Instance of Manila rendered separate decisions, the dispositive part of  which,  except  in  case  No.  L-8620,  is of  the following tenor:

"Por tanto, el Juzgado sobresee esta. causa por falta de  meritos y ordena al ingeniero  de la ciudad  de Manila que haga la demolicion o la remocion  de  las citadas casas, dentro de quince dias despues de liaber avisado al efecto a los aqui  reeurrentes, y  a costa de  los niismos."

In  said case  No.  L-8620,  the  lower  court  rendered judgment as follows:

"In view of the foregoing considerations tile Court hereby declares:

"(a) that the houses of all petitioners in this case erected on the land which forms part of Torres Bugallon, Cavite, Misericordia and Antipolo  Streets constitute public nuisance as denned by  section 1112 of Ordinance No. 1600 of the City of  Manila and by Article 694 paragraphs  4 and 5 of the  Civil  Code and

"(b) that the City  Engineer of the City of Manila is the official authorized  by Article 1112 of Ordinance No. 3600 of the  City of Manila and Article 699, paragraph 3 of the Civil  Code to abate said public nuisance and charge  the expenses thereof  to petitioners."

Petitioners contend  that said  decisions  should  be  reversed  upon  the  ground  that,  in  trying  to  demolish their respective houses  without  notice  and  hearing,  the city engineer sought  to deprive  them of their property without due process of law, apart from the fact that, under Articles 701  and  702 of the new Civil Code,  the power to remove public nuisances is vested in the district health' officer,  not  in  respondent  city  engineer.  It  should  be noted,  however, that,  before  expressing  his  intent  to demolish  the houses in  question,  respondent  had  advised and ordered the petitioners to  remove  said houses, within the  periods  stated in  the  corresponding notices; "that petitioners  do not question, and  have  not questioned,  the: reasonableness  or  sufficiency of  said  periods;  and  that they  have  never asked respondent  herein to  give  them an  opportunity  to  show  that their' houses do not constitute public nuisances.   Besides,  it, is not disputed  that said houses are standing on. public  streets,  with  the  exception of  the  houses  involved  in  cases  Nos. 8518 and 8516, which  are built  on  portions of river  beds.  It is clear,  therefore, that said  houses  are  public  nuisances,' pursuant to  Articles 694 and  695  of the  Civil  Code  of the Philippines, which  is Republic Act No. 386, reading:

Art. 694. "A nuisance is  any  act,  omission, establishment, business, condition  of  property, or anything else which:

"(1) Injures or endangers the health or safety of others; or

"(2) Annoys or offends the senses;  or

"(3) Shocks, defies or disregards decency  or morality; or

"(4) Oblstucts or interferes with  the  free  passage  of  any public  highway  or  street, or  any  body of water; or

"(5) Hinders  or impairs the use of property."'

ART. 695. "Nuisance is  either  public or private.  A public nuisance affects a community  or  neighborhood or any  considerable number  of persons, although the extent ol the annoyance,  danger or damage  upon individuals  may be unequal. A  private nuisance is one that is  not  included  in  the  foregoing  definition."  (Italics supplied.)

It is true that Articles 700  and 702 of the same Code provide: 

ART. 700.- "The district health officer  shall take  care  that one, or all of the remedies against a public  nuisance are  availed  of"

ART.  702. "The district health officer 'shall  determine  whether or not abatement, without judicial proceedings) is  the best remedy against a publie nuisance."

However,  section  31  of  Republic  Act  No.  409,  the Revised  Charter of the City of Manila, specifically places upon the city engineer the  duty;  among others,  "to  have charge of  the  * *  * care ,of * * *   streets,  canals .and esteros  * **"; to "prevent the encroachment of private buildings * * * on the streets  and public places * * *"; to "have supervision * * *  of  all private docks,  wharves, piers * *  * and other property bordering on the harbor, rivers,   esteros   and  waterways * * *  and *  * * issue permits  for the construction, repair  and removal of the same and  enforce all  ordinances relating to the same"; to "have the care  and custody of all sources  of  water supply *  * *"; to "cause buildings  dangerous to the public to be * * *  torn down"; and to "order the removal of buildings and.  structures  erected in violation  of the ordinances *  *  *".   Obviously, articles  700 and  702 of Republic Act No.  386, should yield to  said  section  31 of Republic Act No. 409, not  only because  the former preceded  the latter,  but,  also, because   said  section  31 of Republic  Act No. 409 is a special provision  specifically designed  for the City of Manila, whereas  said Articles 700  and  702  of  the  Civil  Code are general provisions' applicable  throughout the Philippines.  Moreover,  section 1122 of the  Revised  Ordinance  of  the  City of  Manila (No. 1600) explicitly  authorizes  the  action sought to be taken  by  respondent herein, by  providing:

"Whenever the owner or person responsible for any unauthorized obstruction shall, after official notice from  the  proper department, refuse or neglect to remove the same within  a  reasonable time, such obstruction  shall be deemed a public  nuisance,  and the city. engineer is authorized to remove the same at the owner's expense."

Again, houses  constructed,  without governmental authority,  on public streets and  waterways, obstruct at all times the free  use by the public of said streets and waterways,  and, accordingly, constitute nuisances per se,  aside from public  nuisances.  As such,  the summary removal thereof, without judicial, process or proceedings may  be authorized by the statute or municipal ordinance, despite the due process clause.   (66  C.J.S. 733-734.)

"The police power of the  state  justifies the abatement or  destruction, by summary proceedings, of whatever  may be regarded as a public nuisance; and the legislature, may  authorize the  summary  abatement  of  a  nuisance  without judicial  process or proceeding.

"* * * The  remedy of summary abatement  for violation  of a municipal ordinance  may be used  against  a public nuisance." (66 ,C.J.S.  855, 856.)

"When necessary  to  insure the public  safety,  the  legislature may under its  police power authorize municipal authorities  summarily to destroy property without  legal  process or previous notice to the  owner.

 "* * * It is not an objection to  the validity  of a.police  regulation that it does not provide for  a heading or for notice to the owner  before  his property is subjected to restraint or destruction." (12 Am. Jur. 356, 357.)

Municipal Corporations generally  have  power  to cause  the abatement of public nuisances summarily without resort to legal proceedings."  (39 Am.  Jur. 455, 456, 467.)"

Being  in  conformity with  the  facts and the  law,  the decisions appealed from are hereby affirmed in toto,  and the writs of preliminary injunction issued  by the  lower court  dissolved,  with costs against  petitioners-appellants. It is so ordered.

Parás, C.  J., Padilla, Montemayor, Reyes, A. Jugo, Bautista Angelo, Labrador, Reyes,  J. B. L. and Endencia, JJ., concur.